diff --git a/TODO.md b/TODO.md
index a5d2b3dc..95d341c0 100644
--- a/TODO.md
+++ b/TODO.md
@@ -48,4 +48,13 @@
 - [ ]  properly add modularui elements to any gui screen
 - [ ]  a gui to create guis
 - [ ]  sounds ?
-- [ ]  change color of themes to IDrawable
+- [x]  change color of themes to IDrawable
+
+## Internal changes
+- [ ] Clean up IInterpolation
+- [ ] Fix shift clicking to slots which can not be seen
+- [ ] Put axis alignments as inner class into Alignment
+
+## HoloUI
+- [ ] Fix/Remove current rotations
+- [ ] Implement interactions
diff --git a/build.gradle b/build.gradle
index 64673d88..f4a15fa2 100644
--- a/build.gradle
+++ b/build.gradle
@@ -109,6 +109,7 @@ dependencies {
     annotationProcessor('com.google.guava:guava:24.1.1-jre')
     annotationProcessor('com.google.code.gson:gson:2.8.6')
     annotationProcessor(mixin) { transitive = false }
+
     // Example deobf dependency
     // compileOnly rfg.deobf("curse.maven:endercore-231868:2972849:")
 
diff --git a/src/main/java/com/cleanroommc/modularui/api/layout/ILayoutWidget.java b/src/main/java/com/cleanroommc/modularui/api/layout/ILayoutWidget.java
index 3d7c69af..883f2c4e 100644
--- a/src/main/java/com/cleanroommc/modularui/api/layout/ILayoutWidget.java
+++ b/src/main/java/com/cleanroommc/modularui/api/layout/ILayoutWidget.java
@@ -6,13 +6,15 @@
 public interface ILayoutWidget {
 
     /**
-     * Called when this should re-layout it's children.
+     * Called after the children tried to calculate their size.
+     * Might be called multiple times.
      */
     void layoutWidgets();
 
     /**
-     * Can be used for some extra calculations
-     * TODO: Really needed?
+     * Called after post calculation of this widget.
+     * Might be called multiple times.
+     * The last call guarantees, that this widget is fully calculated.
      */
     default void postLayoutWidgets() {
     }
diff --git a/src/main/java/com/cleanroommc/modularui/api/widget/IGuiElement.java b/src/main/java/com/cleanroommc/modularui/api/widget/IGuiElement.java
index faf21e37..d1e8bcfe 100644
--- a/src/main/java/com/cleanroommc/modularui/api/widget/IGuiElement.java
+++ b/src/main/java/com/cleanroommc/modularui/api/widget/IGuiElement.java
@@ -5,6 +5,8 @@
 import com.cleanroommc.modularui.screen.ModularScreen;
 import com.cleanroommc.modularui.screen.viewport.GuiContext;
 import com.cleanroommc.modularui.widget.sizer.Area;
+import com.cleanroommc.modularui.widget.sizer.IResizeable;
+import org.jetbrains.annotations.ApiStatus;
 
 /**
  * Base interface for gui elements. For example widgets.
@@ -21,6 +23,8 @@ public interface IGuiElement {
      */
     IGuiElement getParent();
 
+    IResizeable resizer();
+
     /**
      * @return the area this element occupies
      */
@@ -97,11 +101,6 @@ default boolean isBelowMouse() {
      */
     boolean isEnabled();
 
-    /**
-     * Called when the screen resizes. Handles the positioning and sizing of this element.
-     */
-    void resize();
-
     /**
      * @return default width if it can't be calculated
      */
diff --git a/src/main/java/com/cleanroommc/modularui/api/widget/IWidget.java b/src/main/java/com/cleanroommc/modularui/api/widget/IWidget.java
index d5744612..dd802151 100644
--- a/src/main/java/com/cleanroommc/modularui/api/widget/IWidget.java
+++ b/src/main/java/com/cleanroommc/modularui/api/widget/IWidget.java
@@ -1,7 +1,6 @@
 package com.cleanroommc.modularui.api.widget;
 
 import com.cleanroommc.modularui.api.ITheme;
-import com.cleanroommc.modularui.api.layout.ILayoutWidget;
 import com.cleanroommc.modularui.api.layout.IViewportStack;
 import com.cleanroommc.modularui.drawable.Stencil;
 import com.cleanroommc.modularui.screen.ModularPanel;
@@ -11,7 +10,6 @@
 import com.cleanroommc.modularui.widget.sizer.Flex;
 import com.cleanroommc.modularui.widget.sizer.IResizeable;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 import java.util.Collections;
 import java.util.List;
@@ -130,6 +128,15 @@ default boolean hasChildren() {
 
     void setEnabled(boolean enabled);
 
+    default boolean areAncestorsEnabled() {
+        IWidget parent = this;
+        while (parent != null) {
+            if (!parent.isEnabled()) return false;
+            parent = parent.getParent();
+        }
+        return true;
+    }
+
     default boolean canBeSeen(IViewportStack stack) {
         return Stencil.isInsideScissorArea(getArea(), stack);
     }
@@ -162,7 +169,6 @@ default boolean canHover() {
     /**
      * @return resizer of this widget
      */
-    @Nullable
     IResizeable resizer();
 
     /**
@@ -173,33 +179,20 @@ default boolean canHover() {
     void resizer(IResizeable resizer);
 
     /**
-     * Called when the screen resizes. Handles the positioning and sizing of this element.
+     * Called before a widget is resized.
      */
-    @Override
-    default void resize() {
-        IResizeable resizer = resizer();
-        if (resizer != null) {
-            if (resizer.isSkip()) return;
-            resizer.apply(this);
-        }
-
-        if (hasChildren()) {
-            getChildren().forEach(IWidget::resize);
-        }
-
-        if (this instanceof ILayoutWidget) {
-            ((ILayoutWidget) this).layoutWidgets();
-        }
-
-        if (resizer != null) {
-            resizer.postApply(this);
-        }
+    default void beforeResize() {
+    }
 
-        if (this instanceof ILayoutWidget) {
-            ((ILayoutWidget) this).postLayoutWidgets();
-        }
+    /**
+     * Called after a widget is fully resized.
+     */
+    default void onResized() {
     }
 
+    /**
+     * Called after the full widget tree is resized and the absolute positions are calculated.
+     */
     default void postResize() {
     }
 
diff --git a/src/main/java/com/cleanroommc/modularui/holoui/HoloUI.java b/src/main/java/com/cleanroommc/modularui/holoui/HoloUI.java
index 33b4a6a8..3b7ec26b 100644
--- a/src/main/java/com/cleanroommc/modularui/holoui/HoloUI.java
+++ b/src/main/java/com/cleanroommc/modularui/holoui/HoloUI.java
@@ -1,5 +1,6 @@
 package com.cleanroommc.modularui.holoui;
 
+import com.cleanroommc.modularui.screen.JeiSettings;
 import com.cleanroommc.modularui.screen.ModularScreen;
 import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
 import net.minecraft.client.Minecraft;
@@ -78,6 +79,9 @@ public Builder plane(Plane3D plane) {
         }
 
         public void open(ModularScreen screen) {
+            JeiSettings jeiSettings = new JeiSettings();
+            jeiSettings.disableJei();
+            screen.getContext().setJeiSettings(jeiSettings);
             HoloScreenEntity holoScreenEntity = new HoloScreenEntity(Minecraft.getMinecraft().world, this.plane3D);
             holoScreenEntity.setPosition(this.x, this.y, this.z);
             holoScreenEntity.setScreen(screen);
diff --git a/src/main/java/com/cleanroommc/modularui/manager/GuiCreationContext.java b/src/main/java/com/cleanroommc/modularui/manager/GuiCreationContext.java
index c37d4fd4..050d5de7 100644
--- a/src/main/java/com/cleanroommc/modularui/manager/GuiCreationContext.java
+++ b/src/main/java/com/cleanroommc/modularui/manager/GuiCreationContext.java
@@ -1,5 +1,6 @@
 package com.cleanroommc.modularui.manager;
 
+import com.cleanroommc.modularui.screen.JeiSettings;
 import net.minecraft.block.state.IBlockState;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.item.ItemStack;
@@ -15,15 +16,17 @@ public class GuiCreationContext {
     private final World world;
     private final int x, y, z;
     private final EnumHand hand;
+    private final JeiSettings jeiSettings;
 
     @ApiStatus.Internal
-    public GuiCreationContext(EntityPlayer player, World world, int x, int y, int z, EnumHand hand) {
+    public GuiCreationContext(EntityPlayer player, World world, int x, int y, int z, EnumHand hand, JeiSettings jeiSettings) {
         this.player = player;
         this.world = world;
         this.x = x;
         this.y = y;
         this.z = z;
         this.hand = hand;
+        this.jeiSettings = jeiSettings;
     }
 
     public EntityPlayer getPlayer() {
@@ -78,6 +81,10 @@ public BlockPos getBlockPos() {
         return new BlockPos(this.x, this.y, this.z);
     }
 
+    public JeiSettings getJeiSettings() {
+        return this.jeiSettings;
+    }
+
     public IBlockState getBlockState() {
         BlockPos.PooledMutableBlockPos pos = BlockPos.PooledMutableBlockPos.retain(this.x, this.y, this.z);
         IBlockState blockState = this.world.getBlockState(pos);
@@ -94,7 +101,7 @@ public TileEntity getTileEntity() {
 
     public GuiCreationContext with(EnumHand hand) {
         if (this.hand != hand) {
-            return new GuiCreationContext(this.player, this.world, this.x, this.y, this.z, hand);
+            return new GuiCreationContext(this.player, this.world, this.x, this.y, this.z, hand, this.jeiSettings);
         }
         return this;
     }
diff --git a/src/main/java/com/cleanroommc/modularui/manager/GuiInfo.java b/src/main/java/com/cleanroommc/modularui/manager/GuiInfo.java
index 0caa81c2..e113f137 100644
--- a/src/main/java/com/cleanroommc/modularui/manager/GuiInfo.java
+++ b/src/main/java/com/cleanroommc/modularui/manager/GuiInfo.java
@@ -12,6 +12,7 @@
 import net.minecraftforge.fml.relauncher.Side;
 import net.minecraftforge.fml.relauncher.SideOnly;
 
+import java.util.Objects;
 import java.util.function.BiFunction;
 
 public class GuiInfo {
@@ -49,17 +50,15 @@ public void open(EntityPlayer player, World world, int x, int y, int z) {
     }
 
     public ModularPanel createCommonGui(GuiCreationContext context, GuiSyncManager guiSyncManager) {
-        ModularPanel panel = this.mainPanelCreator.apply(context, guiSyncManager);
+        ModularPanel panel = Objects.requireNonNull(this.mainPanelCreator.apply(context, guiSyncManager), "The main panel must not be null!");
         WidgetTree.collectSyncValues(guiSyncManager, panel);
         return panel;
     }
 
     @SideOnly(Side.CLIENT)
     public ModularScreen createClientGui(GuiCreationContext context, ModularPanel panel) {
-        Object screen = this.clientGuiCreator.apply(context, panel);
-        if (!(screen instanceof ModularScreen)) {
-            throw new IllegalStateException("Client screen must be an instance of ModularScreen");
-        }
+        Object screen = Objects.requireNonNull(this.clientGuiCreator.apply(context, panel), "The modular screen must not be null!");
+        if (!(screen instanceof ModularScreen)) throw new IllegalStateException("Client screen must be an instance of ModularScreen");
         return (ModularScreen) screen;
     }
 
diff --git a/src/main/java/com/cleanroommc/modularui/manager/GuiManager.java b/src/main/java/com/cleanroommc/modularui/manager/GuiManager.java
index 966dc62f..11fac4c3 100644
--- a/src/main/java/com/cleanroommc/modularui/manager/GuiManager.java
+++ b/src/main/java/com/cleanroommc/modularui/manager/GuiManager.java
@@ -2,10 +2,7 @@
 
 import com.cleanroommc.modularui.ModularUI;
 import com.cleanroommc.modularui.network.NetworkUtils;
-import com.cleanroommc.modularui.screen.GuiScreenWrapper;
-import com.cleanroommc.modularui.screen.ModularContainer;
-import com.cleanroommc.modularui.screen.ModularPanel;
-import com.cleanroommc.modularui.screen.ModularScreen;
+import com.cleanroommc.modularui.screen.*;
 import com.cleanroommc.modularui.value.sync.GuiSyncManager;
 import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 import net.minecraft.entity.player.EntityPlayer;
@@ -46,7 +43,7 @@ public Object getServerGuiElement(int ID, EntityPlayer player, World world, int
         GuiInfo info = this.guiInfos.get(ID);
         if (info == null) return null;
         GuiSyncManager guiSyncManager = new GuiSyncManager(player);
-        info.createCommonGui(new GuiCreationContext(player, world, x, y, z, EnumHand.MAIN_HAND), guiSyncManager);
+        info.createCommonGui(new GuiCreationContext(player, world, x, y, z, EnumHand.MAIN_HAND, new JeiSettings()), guiSyncManager);
         return new ModularContainer(guiSyncManager);
     }
 
@@ -56,8 +53,10 @@ public Object getClientGuiElement(int ID, EntityPlayer player, World world, int
         GuiInfo info = this.guiInfos.get(ID);
         if (info == null) return null;
         GuiSyncManager guiSyncManager = new GuiSyncManager(player);
-        GuiCreationContext context = new GuiCreationContext(player, world, x, y, z, EnumHand.MAIN_HAND);
+        GuiCreationContext context = new GuiCreationContext(player, world, x, y, z, EnumHand.MAIN_HAND, new JeiSettings());
         ModularPanel panel = info.createCommonGui(context, guiSyncManager);
-        return new GuiScreenWrapper(new ModularContainer(guiSyncManager), info.createClientGui(context, panel));
+        ModularScreen modularScreen = info.createClientGui(context, panel);
+        modularScreen.getContext().setJeiSettings(context.getJeiSettings());
+        return new GuiScreenWrapper(new ModularContainer(guiSyncManager), modularScreen);
     }
 }
diff --git a/src/main/java/com/cleanroommc/modularui/screen/ModularScreen.java b/src/main/java/com/cleanroommc/modularui/screen/ModularScreen.java
index 75f84a61..dca42225 100644
--- a/src/main/java/com/cleanroommc/modularui/screen/ModularScreen.java
+++ b/src/main/java/com/cleanroommc/modularui/screen/ModularScreen.java
@@ -405,6 +405,10 @@ public ResourceLocation getResourceLocation() {
         return new ResourceLocation(this.owner, this.name);
     }
 
+    public GuiContext getContext() {
+        return this.context;
+    }
+
     public WindowManager getWindowManager() {
         return this.windowManager;
     }
@@ -467,11 +471,6 @@ public ModularScreen useTheme(String theme) {
         return this;
     }
 
-    public ModularScreen useJeiSettings(JeiSettings jeiSettings) {
-        this.context.setJeiSettings(jeiSettings);
-        return this;
-    }
-
     public enum UpOrDown {
         UP(1), DOWN(-1);
 
diff --git a/src/main/java/com/cleanroommc/modularui/screen/viewport/GuiContext.java b/src/main/java/com/cleanroommc/modularui/screen/viewport/GuiContext.java
index 3e9c486a..7b432f3e 100644
--- a/src/main/java/com/cleanroommc/modularui/screen/viewport/GuiContext.java
+++ b/src/main/java/com/cleanroommc/modularui/screen/viewport/GuiContext.java
@@ -54,7 +54,7 @@ public class GuiContext extends GuiViewportStack {
 
     public List<Consumer<GuiContext>> postRenderCallbacks = new ArrayList<>();
 
-    private JeiSettings jeiSettings = new JeiSettings();
+    private JeiSettings jeiSettings;
 
     public GuiContext(ModularScreen screen) {
         this.screen = screen;
@@ -432,10 +432,17 @@ public ITheme getTheme() {
     }
 
     public JeiSettings getJeiSettings() {
+        if (this.jeiSettings == null) {
+            throw new IllegalStateException("The screen is not yet initialised!");
+        }
         return this.jeiSettings;
     }
 
+    @ApiStatus.Internal
     public void setJeiSettings(JeiSettings jeiSettings) {
+        if (this.jeiSettings != null) {
+            throw new IllegalStateException("Tried to set jei settings twice");
+        }
         this.jeiSettings = jeiSettings;
     }
 
diff --git a/src/main/java/com/cleanroommc/modularui/test/EventHandler.java b/src/main/java/com/cleanroommc/modularui/test/EventHandler.java
index c6fbb845..4d35c21a 100644
--- a/src/main/java/com/cleanroommc/modularui/test/EventHandler.java
+++ b/src/main/java/com/cleanroommc/modularui/test/EventHandler.java
@@ -15,6 +15,7 @@ public static void onItemUse(PlayerInteractEvent.RightClickItem event) {
             //GuiManager.openClientUI(Minecraft.getMinecraft().player, new TestGui());
             HoloUI.builder()
                     .inFrontOf(Minecraft.getMinecraft().player, 5, false)
+                    .screenScale(0.5f)
                     .open(new TestGui());
         }
     }
diff --git a/src/main/java/com/cleanroommc/modularui/test/TestTile.java b/src/main/java/com/cleanroommc/modularui/test/TestTile.java
index 3cd35e37..49cd4281 100644
--- a/src/main/java/com/cleanroommc/modularui/test/TestTile.java
+++ b/src/main/java/com/cleanroommc/modularui/test/TestTile.java
@@ -74,6 +74,7 @@ public ModularPanel buildUI(GuiCreationContext guiCreationContext, GuiSyncManage
                 .align(Alignment.Center);    // center the panel in the screen
         panel.bindPlayerInventory()
                 .child(new Row()
+                        .debugName("Tab row")
                         .coverChildren()
                         .topRel(0f, 4, 1f)
                         .child(new PageButton(0, tabController)
@@ -83,18 +84,24 @@ public ModularPanel buildUI(GuiCreationContext guiCreationContext, GuiSyncManage
                         .child(new PageButton(2, tabController)
                                 .tab(GuiTextures.TAB_TOP, 0)))
                 .child(new PagedWidget<>()
+                        .debugName("root parent")
                         .sizeRel(1f)
                         .controller(tabController)
                         .addPage(new ParentWidget<>()
+                                .debugName("page 1 parent")
                                 .sizeRel(1f, 1f)
                                 .child(SlotGroupWidget.playerInventory())
                                 .child(new Row()
+                                        .debugName("buttons, slots and more tests")
                                         .height(137)
+                                        .coverChildrenWidth()
                                         .padding(7)
                                         .child(new Column()
+                                                .debugName("buttons and slots test")
                                                 .coverChildren()
+                                                .marginRight(8)
                                                 //.flex(flex -> flex.height(0.5f))
-                                                .widthRel(0.5f)
+                                                //.widthRel(0.5f)
                                                 .crossAxisAlignment(CrossAxisAlignment.CENTER)
                                                 .child(new ButtonWidget<>()
                                                         .size(60, 18)
@@ -132,10 +139,11 @@ public ModularPanel buildUI(GuiCreationContext guiCreationContext, GuiSyncManage
                                                         .size(60, 20)
                                                         .value(SyncHandlers.doubleNumber(() -> this.doubleValue, val -> this.doubleValue = val))
                                                         .setNumbersDouble(Function.identity()))
-                                                .child(IKey.str("Test string").asWidget().padding(2)))
+                                                .child(IKey.str("Test string").asWidget().padding(2).debugName("test string")))
                                         .child(new Column()
+                                                .debugName("button and slots test 2")
                                                 .coverChildren()
-                                                .widthRel(0.5f)
+                                                //.widthRel(0.5f)
                                                 .crossAxisAlignment(CrossAxisAlignment.CENTER)
                                                 .child(new ProgressWidget()
                                                         .progress(() -> this.progress / (double) this.duration)
@@ -160,6 +168,7 @@ public ModularPanel buildUI(GuiCreationContext guiCreationContext, GuiSyncManage
                                                         .syncHandler(SyncHandlers.fluidSlot(this.fluidTankPhantom).phantom(true)))
                                         )))
                         .addPage(new Column()
+                                        .debugName("Slots test page")
                                         //.coverChildren()
                                         .padding(7)
                                         .child(SlotGroupWidget.playerInventory())
@@ -197,6 +206,7 @@ public ModularPanel buildUI(GuiCreationContext guiCreationContext, GuiSyncManage
                                 .asWidget()
                                 .flex(flex -> flex.width(1f).height(1f))*/)
                         .addPage(new ParentWidget<>()
+                                .debugName("page 3 parent")
                                 .sizeRel(1f, 1f)
                                 .padding(7)
                                 .child(SlotGroupWidget.playerInventory())
@@ -206,6 +216,7 @@ public ModularPanel buildUI(GuiCreationContext guiCreationContext, GuiSyncManage
                                         .stopper(0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100)
                                         .background(GuiTextures.SLOT_DARK))
                                 .child(new ButtonWidget<>()
+                                        .debugName("color picker button")
                                         .top(25)
                                         .background(colorPickerBackground)
                                         .onMousePressed(mouseButton -> {
@@ -223,7 +234,9 @@ public ModularPanel buildUI(GuiCreationContext guiCreationContext, GuiSyncManage
                                                 .left(32)
                                                 .size(1, 40))*/
                                         .child(new Row()
-                                                .widthRel(1f).height(14)
+                                                .debugName("bogo test config 1")
+                                                .widthRel(1f).coverChildrenHeight()
+                                                .crossAxisAlignment(CrossAxisAlignment.CENTER)
                                                 .child(new CycleButtonWidget()
                                                         .value(new BoolValue(false))
                                                         .texture(GuiTextures.CHECK_BOX)
@@ -233,6 +246,7 @@ public ModularPanel buildUI(GuiCreationContext guiCreationContext, GuiSyncManage
                                                         .height(14)
                                                         .marginLeft(10)))
                                         .child(new Row()
+                                                .debugName("bogo test config 2")
                                                 .widthRel(1f).height(14)
                                                 .child(new TextFieldWidget()
                                                         .value(new IntValue.Dynamic(() -> this.num, val -> this.num = val))
@@ -250,6 +264,7 @@ public ModularPanel buildUI(GuiCreationContext guiCreationContext, GuiSyncManage
                                                 .tooltip(tooltip -> tooltip.showUpTimer(10)
                                                         .addLine(IKey.lang("bogosort.gui.hotbar_scrolling.tooltip"))))
                                         .child(new Row()
+                                                .debugName("bogo test config 3")
                                                 .widthRel(1f).height(14)
                                                 .child(new CycleButtonWidget()
                                                         .value(new BoolValue(false))
diff --git a/src/main/java/com/cleanroommc/modularui/value/sync/GuiSyncManager.java b/src/main/java/com/cleanroommc/modularui/value/sync/GuiSyncManager.java
index 22b14e38..9fabff2e 100644
--- a/src/main/java/com/cleanroommc/modularui/value/sync/GuiSyncManager.java
+++ b/src/main/java/com/cleanroommc/modularui/value/sync/GuiSyncManager.java
@@ -179,6 +179,10 @@ public PlayerMainInvWrapper getPlayerInventory() {
         return this.playerInventory;
     }
 
+    public boolean isClient() {
+        return NetworkUtils.isClient(this.player);
+    }
+
     public static String makeSyncKey(String name, int id) {
         return name + ":" + id;
     }
diff --git a/src/main/java/com/cleanroommc/modularui/value/sync/PanelSyncHandler.java b/src/main/java/com/cleanroommc/modularui/value/sync/PanelSyncHandler.java
index 17369f47..3f963627 100644
--- a/src/main/java/com/cleanroommc/modularui/value/sync/PanelSyncHandler.java
+++ b/src/main/java/com/cleanroommc/modularui/value/sync/PanelSyncHandler.java
@@ -1,6 +1,5 @@
 package com.cleanroommc.modularui.value.sync;
 
-import com.cleanroommc.modularui.network.NetworkUtils;
 import com.cleanroommc.modularui.screen.ModularPanel;
 import com.cleanroommc.modularui.widget.WidgetTree;
 import net.minecraft.network.PacketBuffer;
@@ -11,6 +10,7 @@
 public abstract class PanelSyncHandler extends SyncHandler {
 
     private final ModularPanel mainPanel;
+    private ModularPanel openedPanel;
 
     protected PanelSyncHandler(ModularPanel mainPanel) {
         this.mainPanel = mainPanel;
@@ -23,9 +23,9 @@ public void openPanel() {
     }
 
     private void openPanel(boolean syncToServer) {
-        boolean client = NetworkUtils.isClient(getSyncManager().getPlayer());
+        boolean client = getSyncManager().isClient();
         if (syncToServer && client) {
-            syncToServer(0, buffer -> {});
+            syncToServer(0);
             return;
         }
         ModularPanel panel = Objects.requireNonNull(createUI(this.mainPanel, getSyncManager()));
@@ -35,13 +35,29 @@ private void openPanel(boolean syncToServer) {
         WidgetTree.collectSyncValues(getSyncManager(), panel);
         if (client && !this.mainPanel.getScreen().isPanelOpen(panel.getName())) {
             this.mainPanel.getScreen().openPanel(panel);
+            this.openedPanel = panel;
         }
     }
 
+    public void closePanel() {
+        if (getSyncManager().isClient()) {
+            if (this.openedPanel != null) this.openedPanel.animateClose();
+        } else {
+            syncToClient(2);
+        }
+        this.openedPanel = null;
+    }
+
+    public boolean isPanelOpen() {
+        return this.openedPanel != null && (!getSyncManager().isClient() || this.openedPanel.isOpen());
+    }
+
     @Override
     public void readOnClient(int i, PacketBuffer packetBuffer) throws IOException {
         if (i == 1) {
             openPanel(false);
+        } else if (i == 2) {
+            closePanel();
         }
     }
 
@@ -49,7 +65,7 @@ public void readOnClient(int i, PacketBuffer packetBuffer) throws IOException {
     public void readOnServer(int i, PacketBuffer packetBuffer) throws IOException {
         if (i == 0) {
             openPanel(false);
-            syncToClient(1, buf -> {});
+            syncToClient(1);
         }
     }
 }
diff --git a/src/main/java/com/cleanroommc/modularui/value/sync/SyncHandler.java b/src/main/java/com/cleanroommc/modularui/value/sync/SyncHandler.java
index a2f9d012..f4f9789b 100644
--- a/src/main/java/com/cleanroommc/modularui/value/sync/SyncHandler.java
+++ b/src/main/java/com/cleanroommc/modularui/value/sync/SyncHandler.java
@@ -1,7 +1,6 @@
 package com.cleanroommc.modularui.value.sync;
 
 import com.cleanroommc.modularui.network.NetworkHandler;
-import com.cleanroommc.modularui.network.NetworkUtils;
 import com.cleanroommc.modularui.network.packets.PacketSyncHandler;
 import io.netty.buffer.Unpooled;
 import net.minecraft.entity.player.EntityPlayerMP;
@@ -10,6 +9,7 @@
 import net.minecraftforge.fml.relauncher.SideOnly;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.MustBeInvokedByOverriders;
+import org.jetbrains.annotations.NotNull;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -38,7 +38,7 @@ public void init(String key, GuiSyncManager syncManager) {
      * @param id             an internal denominator to identify this package
      * @param bufferConsumer the package builder
      */
-    public final void syncToClient(int id, Consumer<PacketBuffer> bufferConsumer) {
+    public final void syncToClient(int id, @NotNull Consumer<PacketBuffer> bufferConsumer) {
         PacketBuffer buffer = new PacketBuffer(Unpooled.buffer());
         buffer.writeVarInt(id);
         bufferConsumer.accept(buffer);
@@ -52,7 +52,7 @@ public final void syncToClient(int id, Consumer<PacketBuffer> bufferConsumer) {
      * @param bufferConsumer the package builder
      */
     @SideOnly(Side.CLIENT)
-    public final void syncToServer(int id, Consumer<PacketBuffer> bufferConsumer) {
+    public final void syncToServer(int id, @NotNull Consumer<PacketBuffer> bufferConsumer) {
         PacketBuffer buffer = new PacketBuffer(Unpooled.buffer());
         buffer.writeVarInt(id);
         bufferConsumer.accept(buffer);
@@ -65,17 +65,44 @@ public final void syncToServer(int id, Consumer<PacketBuffer> bufferConsumer) {
      * @param id             an internal denominator to identify this package
      * @param bufferConsumer the package builder
      */
-    public final void sync(int id, Consumer<PacketBuffer> bufferConsumer) {
+    public final void sync(int id, @NotNull Consumer<PacketBuffer> bufferConsumer) {
         PacketBuffer buffer = new PacketBuffer(Unpooled.buffer());
         buffer.writeVarInt(id);
         bufferConsumer.accept(buffer);
-        if (NetworkUtils.isClient(getSyncManager().getPlayer())) {
+        if (getSyncManager().isClient()) {
             sendToServer(buffer, this);
         } else {
             sendToClient(buffer, this);
         }
     }
 
+    /**
+     * Sends an empty packte to the client with an id.
+     *
+     * @param id identifier
+     */
+    public final void syncToClient(int id) {
+        syncToClient(id, buf -> {});
+    }
+
+    /**
+     * Sends an empty packte to the server with an id.
+     *
+     * @param id identifier
+     */
+    public final void syncToServer(int id) {
+        syncToServer(id, buf -> {});
+    }
+
+    /**
+     * Sends an empty packte to the other side with an id.
+     *
+     * @param id identifier
+     */
+    public final void sync(int id) {
+        sync(id, buf -> {});
+    }
+
     /**
      * Called when this sync handler receives a packet on client.
      *
diff --git a/src/main/java/com/cleanroommc/modularui/widget/ScrollWidget.java b/src/main/java/com/cleanroommc/modularui/widget/ScrollWidget.java
index b00f629f..53cd5a47 100644
--- a/src/main/java/com/cleanroommc/modularui/widget/ScrollWidget.java
+++ b/src/main/java/com/cleanroommc/modularui/widget/ScrollWidget.java
@@ -65,8 +65,7 @@ public void getWidgetsAt(IViewportStack stack, IWidgetList widgets, int x, int y
     }
 
     @Override
-    public void resize() {
-        super.resize();
+    public void onResized() {
         if (this.scroll.getScrollX() != null) {
             this.scroll.getScrollX().clamp(this.scroll);
         }
diff --git a/src/main/java/com/cleanroommc/modularui/widget/WidgetTree.java b/src/main/java/com/cleanroommc/modularui/widget/WidgetTree.java
index 6f43302f..20d0ac23 100644
--- a/src/main/java/com/cleanroommc/modularui/widget/WidgetTree.java
+++ b/src/main/java/com/cleanroommc/modularui/widget/WidgetTree.java
@@ -1,5 +1,6 @@
 package com.cleanroommc.modularui.widget;
 
+import com.cleanroommc.modularui.api.layout.ILayoutWidget;
 import com.cleanroommc.modularui.api.layout.IViewport;
 import com.cleanroommc.modularui.api.widget.IGuiElement;
 import com.cleanroommc.modularui.api.widget.ISynced;
@@ -22,8 +23,6 @@
  */
 public class WidgetTree {
 
-    private static final String AUTO_SYNC_KEY = "auto$sync";
-
     private WidgetTree() {
     }
 
@@ -211,15 +210,67 @@ public static void onFrameUpdate(IWidget parent) {
 
     public static void resize(IWidget parent) {
         // resize each widget and calculate their relative pos
-        parent.resize();
+        if (!resizeWidget(parent, true) && !resizeWidget(parent, false)) {
+            throw new IllegalStateException("Failed to resize widgets");
+        }
         // now apply the calculated pos
         applyPos(parent);
         WidgetTree.foreachChildByLayer(parent, child -> {
             child.postResize();
+            //ModularUI.LOGGER.info("{} at {}", child, child.getArea());
             return true;
         }, true);
     }
 
+    private static boolean resizeWidget(IWidget widget, boolean init) {
+        boolean result = false;
+        // first try to resize this widget
+        IResizeable resizer = widget.resizer();
+        if (resizer != null) {
+            if (init) {
+                widget.beforeResize();
+                resizer.initResizing();
+            }
+            result = resizer.resize(widget);
+        }
+
+        // now resize all children and collect children which could not be fully calculated
+        List<IWidget> anotherResize = new ArrayList<>();
+        if (widget.hasChildren()) {
+            widget.getChildren().forEach(iWidget -> {
+                if (!resizeWidget(iWidget, init)) {
+                    anotherResize.add(iWidget);
+                }
+            });
+        }
+
+        if (widget instanceof ILayoutWidget) {
+            ((ILayoutWidget) widget).layoutWidgets();
+        }
+
+        // post resize this widget if possible
+        if (resizer != null && !result) {
+            result = resizer.postResize(widget);
+        }
+
+        if (widget instanceof ILayoutWidget) {
+            ((ILayoutWidget) widget).postLayoutWidgets();
+        }
+
+        // now fully resize all children which needs it
+        if (!anotherResize.isEmpty()) {
+            anotherResize.forEach(iWidget -> {
+                if (!iWidget.resizer().isFullyCalculated()) {
+                    resizeWidget(iWidget, false);
+                }
+            });
+        }
+
+        if (result) widget.onResized();
+
+        return result;
+    }
+
     public static void applyPos(IWidget parent) {
         WidgetTree.foreachChildByLayer(parent, child -> {
             IResizeable resizer = child.resizer();
diff --git a/src/main/java/com/cleanroommc/modularui/widget/sizer/Area.java b/src/main/java/com/cleanroommc/modularui/widget/sizer/Area.java
index 2f41e9b5..3b5dafd6 100644
--- a/src/main/java/com/cleanroommc/modularui/widget/sizer/Area.java
+++ b/src/main/java/com/cleanroommc/modularui/widget/sizer/Area.java
@@ -328,15 +328,60 @@ public Box getPadding() {
     }
 
     @Override
-    public void apply(IGuiElement guiElement) {
+    public void initResizing() {
+    }
+
+    @Override
+    public boolean resize(IGuiElement guiElement) {
         guiElement.getArea().set(this);
+        return true;
+    }
+
+    @Override
+    public boolean postResize(IGuiElement guiElement) {
+        return true;
+    }
+
+    @Override
+    public Area getArea() {
+        return this;
+    }
+
+    @Override
+    public boolean isXCalculated() {
+        return true;
     }
 
     @Override
-    public void postApply(IGuiElement guiElement) {
+    public boolean isYCalculated() {
+        return true;
+    }
+
+    @Override
+    public boolean isWidthCalculated() {
+        return true;
+    }
+
+    @Override
+    public boolean isHeightCalculated() {
+        return true;
+    }
+
+    @Override
+    public void setResized(boolean x, boolean y, boolean w, boolean h) {
     }
 
     public Area createCopy() {
         return new Area(this);
     }
+
+    @Override
+    public String toString() {
+        return "Area{" +
+                "x=" + this.x +
+                ", y=" + this.y +
+                ", width=" + this.width +
+                ", height=" + this.height +
+                '}';
+    }
 }
diff --git a/src/main/java/com/cleanroommc/modularui/widget/sizer/DimensionSizer.java b/src/main/java/com/cleanroommc/modularui/widget/sizer/DimensionSizer.java
index 328d0102..19947498 100644
--- a/src/main/java/com/cleanroommc/modularui/widget/sizer/DimensionSizer.java
+++ b/src/main/java/com/cleanroommc/modularui/widget/sizer/DimensionSizer.java
@@ -13,6 +13,8 @@ public class DimensionSizer {
     private boolean cancelAutoMovement = false;
     private boolean defaultMode = false;
 
+    private boolean posCalculated = false, sizeCalculated = false;
+
     public DimensionSizer(GuiAxis axis) {
         this.axis = axis;
     }
@@ -76,6 +78,14 @@ public boolean hasSize() {
         return this.size != null;
     }
 
+    public boolean isSizeCalculated() {
+        return this.sizeCalculated;
+    }
+
+    public boolean isPosCalculated() {
+        return this.posCalculated;
+    }
+
     public boolean dependsOnChildren() {
         return this.coverChildren;
     }
@@ -86,54 +96,107 @@ public boolean dependsOnParent() {
                 (this.size != null && this.size.isRelative());
     }
 
-    public void apply(Area area, Area relativeTo, IntSupplier defaultSize) {
+    public void setResized(boolean all) {
+        setResized(all, all);
+    }
+
+    public void setResized(boolean pos, boolean size) {
+        this.posCalculated = pos;
+        this.sizeCalculated = size;
+    }
+
+    private boolean needsSize(Unit unit) {
+        return unit.isRelative() && unit.getAnchor() != 0;
+    }
+
+    public void apply(Area area, IResizeable relativeTo, IntSupplier defaultSize) {
+        if (this.sizeCalculated && this.posCalculated) return;
         int p, s;
-        int parentSize = relativeTo.getSize(this.axis);
+        int parentSize = relativeTo.getArea().getSize(this.axis);
+        boolean calcParent = relativeTo.isSizeCalculated(this.axis);
 
-        // calc start, end and size
-        if (this.start == null && this.end == null) {
-            p = 0;
-            s = this.size == null ? defaultSize.getAsInt() : calcSize(this.size, parentSize);
+        if (this.sizeCalculated && !this.posCalculated) {
+            s = area.getSize(this.axis);
+            if (this.start != null) {
+                p = calcPoint(this.start, s, parentSize, calcParent);
+            } else if (this.end != null) {
+                p = calcPoint(this.end, s, parentSize, calcParent);
+            } else {
+                throw new IllegalStateException();
+            }
+        } else if (!this.sizeCalculated && this.posCalculated) {
+            p = area.getRelativePoint(this.axis);
+            if (this.size != null) {
+                s = this.coverChildren ? 18 : calcSize(this.size, parentSize, calcParent);
+            } else {
+                s = defaultSize.getAsInt();
+                this.sizeCalculated = s > 0;
+            }
         } else {
-            if (this.size == null) {
-                if (this.start != null && this.end != null) {
-                    p = calcPoint(this.start, -1, parentSize);
-                    int x2 = calcPoint(this.end, -1, parentSize);
-                    s = Math.abs(parentSize - x2 - p);
-                } else {
+            // calc start, end and size
+            if (this.start == null && this.end == null) {
+                p = 0;
+                if (this.size == null) {
                     s = defaultSize.getAsInt();
-                    if (this.start == null) {
-                        p = calcPoint(this.end, s, parentSize);
-                        p -= s;
+                    this.sizeCalculated = s > 0;
+                } else {
+                    s = calcSize(this.size, parentSize, calcParent);
+                }
+                this.posCalculated = true;
+            } else {
+                if (this.size == null) {
+                    if (this.start != null && this.end != null) {
+                        p = calcPoint(this.start, -1, parentSize, calcParent);
+                        boolean b = this.posCalculated;
+                        this.posCalculated = false;
+                        int x2 = calcPoint(this.end, -1, parentSize, calcParent);
+                        s = Math.abs(parentSize - x2 - p);
+                        this.posCalculated &= b;
+                        this.sizeCalculated |= this.posCalculated;
                     } else {
-                        p = calcPoint(this.start, s, parentSize);
+                        s = defaultSize.getAsInt();
+                        this.sizeCalculated = s > 0;
+                        if (this.start == null) {
+                            p = calcPoint(this.end, s, parentSize, calcParent);
+                            p -= s;
+                            this.posCalculated &= this.sizeCalculated;
+                        } else {
+                            p = calcPoint(this.start, s, parentSize, calcParent);
+                            this.posCalculated &= (this.sizeCalculated || !needsSize(this.start));
+                        }
                     }
+                } else if (this.start != null) {
+                    s = calcSize(this.size, parentSize, calcParent);
+                    p = calcPoint(this.start, s, parentSize, calcParent);
+                    this.posCalculated &= (this.sizeCalculated || !needsSize(this.start));
+                } else {
+                    s = calcSize(this.size, parentSize, calcParent);
+                    p = calcPoint(this.end, s, parentSize, calcParent);
+                    p = parentSize - p - s;
+                    this.posCalculated &= this.sizeCalculated;
                 }
-            } else if (this.end == null) {
-                s = calcSize(this.size, parentSize);
-                p = calcPoint(this.start, s, parentSize);
-            } else {
-                s = calcSize(this.size, parentSize);
-                p = calcPoint(this.end, s, parentSize);
-                p = parentSize - p - s;
             }
         }
 
         // apply padding and margin
-        Box.SHARED.all(0);
-        Box padding = relativeTo.getPadding();
-        Box margin = area.getMargin();
+        if (this.posCalculated && this.sizeCalculated) {
+            Box.SHARED.all(0);
+            Box padding = relativeTo.getArea().getPadding();
+            Box margin = area.getMargin();
+
+            if (parentSize < 1 || (this.size != null && !this.size.isRelative())) {
+                area.setRelativePoint(this.axis, p);
+            } else {
+                area.setRelativePoint(this.axis, Math.max(p, padding.getStart(this.axis) + margin.getStart(this.axis)));
+                s = Math.min(s, parentSize - padding.getTotal(this.axis) - margin.getTotal(this.axis));
+            }
 
-        if (parentSize < 1 || (this.size != null && !this.size.isRelative())) {
-            area.setRelativePoint(this.axis, p);
         } else {
-            area.setRelativePoint(this.axis, Math.max(p, padding.getStart(this.axis) + margin.getStart(this.axis)));
-            s = Math.min(s, parentSize - padding.getTotal(this.axis) - margin.getTotal(this.axis));
+            area.setRelativePoint(this.axis, p);
         }
-
-        p += relativeTo.x;
+        p += relativeTo.getArea().x;
+        area.setPoint(this.axis, p); // temporary
         area.setSize(this.axis, s);
-        area.setPoint(this.axis, p);
     }
 
     public int postApply(Area area, Area relativeTo, int p0, int p1) {
@@ -141,41 +204,50 @@ public int postApply(Area area, Area relativeTo, int p0, int p1) {
         // calculate width and recalculate x based on the new width
         int s = p1 - p0, p;
         area.setSize(this.axis, s);
-        if (this.start != null) {
-            p = calcPoint(this.start, s, relativeTo.getSize(this.axis));
-        } else if (this.end != null) {
-            p = calcPoint(this.end, s, relativeTo.getSize(this.axis));
-            p = relativeTo.getSize(this.axis) - p - s;
-        } else {
-            p = area.getRelativePoint(this.axis) + p0 + area.getMargin().getStart(this.axis);
-            if (!this.cancelAutoMovement) {
-                moveAmount = -p0;
+        this.sizeCalculated = true;
+        if (!isPosCalculated()) {
+            if (this.start != null) {
+                p = calcPoint(this.start, s, relativeTo.getSize(this.axis), true);
+            } else if (this.end != null) {
+                p = calcPoint(this.end, s, relativeTo.getSize(this.axis), true);
+                p = relativeTo.getSize(this.axis) - p - s;
+            } else {
+                p = area.getRelativePoint(this.axis) + p0 + area.getMargin().getStart(this.axis);
+                if (!this.cancelAutoMovement) {
+                    moveAmount = -p0;
+                }
             }
+            area.setRelativePoint(this.axis, p);
+            this.posCalculated = true;
         }
-        area.setRelativePoint(this.axis, p);
         return moveAmount;
     }
 
-    private int calcSize(Unit s, int parentSize) {
+    private int calcSize(Unit s, int parentSize, boolean parentSizeCalculated) {
+        if (this.coverChildren) return 18;
         float val = s.getValue();
         if (s.isRelative()) {
-            return (int) (val * parentSize);
+            if (!parentSizeCalculated) return (int) val;
+            val *= parentSize;
         }
+        this.sizeCalculated = true;
         return (int) val;
     }
 
-    public int calcPoint(Unit p, int width, int parentSize) {
+    public int calcPoint(Unit p, int width, int parentSize, boolean parentSizeCalculated) {
         float val = p.getValue();
+        if (!parentSizeCalculated && (p == this.end || p.isRelative())) return (int) val;
         if (p.isRelative()) {
             val = parentSize * val;
+            float anchor = p.getAnchor();
+            if (width > 0 && anchor != 0) {
+                val -= width * anchor;
+            }
+            if (p.getOffset() != 0) {
+                val += p.getOffset();
+            }
         }
-        float anchor = p.getAnchor();
-        if (width > 0 && anchor != 0) {
-            val -= width * anchor;
-        }
-        if (p.getOffset() != 0) {
-            val += p.getOffset();
-        }
+        this.posCalculated = true;
         return (int) val;
     }
 
diff --git a/src/main/java/com/cleanroommc/modularui/widget/sizer/Flex.java b/src/main/java/com/cleanroommc/modularui/widget/sizer/Flex.java
index df2f26da..3627f2fa 100644
--- a/src/main/java/com/cleanroommc/modularui/widget/sizer/Flex.java
+++ b/src/main/java/com/cleanroommc/modularui/widget/sizer/Flex.java
@@ -1,6 +1,7 @@
 package com.cleanroommc.modularui.widget.sizer;
 
 import com.cleanroommc.modularui.GuiError;
+import com.cleanroommc.modularui.api.layout.ILayoutWidget;
 import com.cleanroommc.modularui.api.widget.IGuiElement;
 import com.cleanroommc.modularui.api.widget.IPositioned;
 import com.cleanroommc.modularui.api.widget.IVanillaSlot;
@@ -20,7 +21,6 @@ public class Flex implements IResizeable, IPositioned<Flex> {
     private final IGuiElement parent;
     private Area relativeTo;
     private boolean relativeToParent = true;
-    private boolean skip = false;
 
     public Flex(IGuiElement parent) {
         this.parent = parent;
@@ -58,6 +58,26 @@ public Area getArea() {
         return this.parent.getArea();
     }
 
+    @Override
+    public boolean isXCalculated() {
+        return this.x.isPosCalculated();
+    }
+
+    @Override
+    public boolean isYCalculated() {
+        return this.y.isPosCalculated();
+    }
+
+    @Override
+    public boolean isWidthCalculated() {
+        return this.x.isSizeCalculated();
+    }
+
+    @Override
+    public boolean isHeightCalculated() {
+        return this.y.isSizeCalculated();
+    }
+
     public Flex coverChildrenWidth() {
         this.x.setCoverChildren(true);
         return this;
@@ -226,8 +246,9 @@ public Flex anchor(Alignment alignment) {
         return this;
     }
 
-    private Area getRelativeTo() {
-        Area relativeTo = this.relativeToParent ? this.parent.getParentArea() : this.relativeTo;
+    private IResizeable getRelativeTo() {
+        IGuiElement parent = this.parent.getParent();
+        IResizeable relativeTo = this.relativeToParent && parent != null ? parent.resizer() : this.relativeTo;
         return relativeTo != null ? relativeTo : this.parent.getScreen().getScreenArea();
     }
 
@@ -263,54 +284,43 @@ public boolean hasFixedSize() {
         return this.x.hasFixedSize() && this.y.hasFixedSize();
     }
 
-    @ApiStatus.Internal
-    public void skip() {
-        this.skip = true;
+    @Override
+    public void initResizing() {
+        this.x.setResized(false);
+        this.y.setResized(false);
     }
 
     @Override
-    public boolean isSkip() {
-        return this.skip;
+    public void setResized(boolean x, boolean y, boolean w, boolean h) {
+        this.x.setResized(x, w);
+        this.y.setResized(y, h);
     }
 
     @Override
-    public void apply(IGuiElement guiElement) {
-        if (isSkip()) return;
-        Area relativeTo = getRelativeTo();
+    public boolean resize(IGuiElement guiElement) {
+        IResizeable relativeTo = getRelativeTo();
+        Area relativeArea = relativeTo.getArea();
         byte panelLayer = this.parent.getArea().getPanelLayer();
 
-        if (relativeTo.getPanelLayer() > panelLayer ||
-                (relativeTo.getPanelLayer() == panelLayer && relativeTo.z() >= this.parent.getArea().z())) {
+        if (relativeArea.getPanelLayer() > panelLayer ||
+                (relativeArea.getPanelLayer() == panelLayer && relativeArea.z() >= this.parent.getArea().z())) {
             GuiError.throwNew(this.parent, GuiError.Type.SIZING, "Widget can't be relative to a widget at the same level or above");
-            return;
-        }
-
-        // check if children area is required for this widget
-        if (this.x.dependsOnChildren() || this.y.dependsOnChildren()) {
-            if (!(this.parent instanceof IWidget)) {
-                throw new IllegalStateException("Can only cover children if instance of IWidget");
-            }
-
-            IWidget widget = (IWidget) this.parent;
-
-            List<IWidget> children = widget.getChildren();
-            if (!children.isEmpty()) {
-                for (IWidget child : children) {
-                    if (dependsOnThis(child, null)) {
-                        // children area requires this area to be calculated and will be skipped
-                        child.flex().skip();
-                    }
-                }
-            }
+            return true;
         }
 
         // calculate x, y, width and height if possible
         this.x.apply(guiElement.getArea(), relativeTo, guiElement::getDefaultWidth);
         this.y.apply(guiElement.getArea(), relativeTo, guiElement::getDefaultHeight);
+        return isFullyCalculated();
     }
 
     @Override
-    public void postApply(IGuiElement guiElement) {
+    public boolean postResize(IGuiElement guiElement) {
+        if (this.parent instanceof ILayoutWidget) {
+            coverChildrenForLayout();
+            return true;
+        }
+
         // not skipped children are now calculated and now this area can be calculated if it requires childrens area
         if (this.x.dependsOnChildren() || this.y.dependsOnChildren()) {
             List<IWidget> children = ((IWidget) this.parent).getChildren();
@@ -322,20 +332,20 @@ public void postApply(IGuiElement guiElement) {
                 int x0 = Integer.MAX_VALUE, x1 = Integer.MIN_VALUE, y0 = Integer.MAX_VALUE, y1 = Integer.MIN_VALUE;
                 for (IWidget child : children) {
                     Box margin = child.getArea().getMargin();
-                    Flex flex = child.flex();
+                    IResizeable resizeable = child.resizer();
                     Area area = child.getArea();
-                    if (this.x.dependsOnChildren() && !dependsOnThis(child, GuiAxis.X)) {
+                    if (this.x.dependsOnChildren() && resizeable.isWidthCalculated()) {
                         x0 = Math.min(x0, area.rx - padding.left - margin.left);
                         x1 = Math.max(x1, area.rx + area.width + padding.right + margin.right);
                     }
-                    if (this.y.dependsOnChildren() && !dependsOnThis(child, GuiAxis.Y)) {
+                    if (this.y.dependsOnChildren() && resizeable.isHeightCalculated()) {
                         y0 = Math.min(y0, area.ry - padding.top - margin.top);
                         y1 = Math.max(y1, area.ry + area.height + padding.bottom + margin.bottom);
                     }
                 }
 
                 // now calculate new x, y, width and height based on the childrens area
-                Area relativeTo = getRelativeTo();
+                Area relativeTo = getRelativeTo().getArea();
                 if (this.x.dependsOnChildren()) {
                     moveChildrenX = this.x.postApply(this.parent.getArea(), relativeTo, x0, x1);
                 }
@@ -343,26 +353,49 @@ public void postApply(IGuiElement guiElement) {
                     moveChildrenY = this.y.postApply(this.parent.getArea(), relativeTo, y0, y1);
                 }
                 for (IWidget widget : children) {
-                    if (widget.flex().isSkip()) {
-                        // child was skipped before
-                        // this area is now calculated and child can now be calculated
-                        widget.flex().skip = false;
-                        widget.resize();
-                    } else {
-                        // child was already calculated and now needs to be moved, so that child stays in the same spot and doesn't get moved with the whole parent
-                        Area area = widget.getArea();
-                        area.rx += moveChildrenX;
-                        area.ry += moveChildrenY;
+                    Area area = widget.getArea();
+                    IResizeable resizeable = widget.resizer();
+                    if (resizeable.isXCalculated()) area.rx += moveChildrenX;
+                    if (resizeable.isYCalculated()) area.ry += moveChildrenY;
+                }
+            }
+        }
+        return isFullyCalculated();
+    }
+
+    private void coverChildrenForLayout() {
+        if (this.x.dependsOnChildren() || this.y.dependsOnChildren()) {
+            List<IWidget> children = ((IWidget) this.parent).getChildren();
+            if (!children.isEmpty()) {
+                Box padding = this.parent.getArea().getPadding();
+                // first calculate the area the children span
+                int x0 = Integer.MAX_VALUE, x1 = Integer.MIN_VALUE, y0 = Integer.MAX_VALUE, y1 = Integer.MIN_VALUE;
+                for (IWidget child : children) {
+                    Box margin = child.getArea().getMargin();
+                    IResizeable resizeable = child.resizer();
+                    Area area = child.getArea();
+                    if (this.x.dependsOnChildren() && resizeable.isWidthCalculated()) {
+                        x1 = Math.max(x1, area.rx + area.width + padding.right + margin.right);
+                    }
+                    if (this.y.dependsOnChildren() && resizeable.isHeightCalculated()) {
+                        y1 = Math.max(y1, area.ry + area.height + padding.bottom + margin.bottom);
                     }
                 }
+                Area relativeTo = getRelativeTo().getArea();
+                if (this.x.dependsOnChildren()) {
+                    this.x.postApply(getArea(), relativeTo, 0, x1);
+                }
+                if (this.y.dependsOnChildren()) {
+                    this.y.postApply(getArea(), relativeTo, 0, y1);
+                }
             }
         }
     }
 
     @Override
     public void applyPos(IGuiElement parent) {
-        // after all widgets x, y, width and height have been calculated when can now calculate the absolute position
-        Area relativeTo = getRelativeTo();
+        // after all widgets x, y, width and height have been calculated we can now calculate the absolute position
+        Area relativeTo = getRelativeTo().getArea();
         Area area = parent.getArea();
         area.applyPos(relativeTo.x, relativeTo.y);
         Area parentArea = parent.getParentArea();
@@ -375,12 +408,6 @@ public void applyPos(IGuiElement parent) {
         }
     }
 
-    private boolean dependsOnThis(IWidget child, GuiAxis axis) {
-        Flex flex = child.getFlex();
-        if (flex == null || flex.getRelativeTo() != this.parent.getArea()) return false;
-        return axis == null ? flex.x.dependsOnParent() || flex.y.dependsOnParent() : axis == GuiAxis.X ? flex.x.dependsOnParent() : flex.y.dependsOnParent();
-    }
-
     private Unit getLeft() {
         return this.x.getStart();
     }
diff --git a/src/main/java/com/cleanroommc/modularui/widget/sizer/IResizeable.java b/src/main/java/com/cleanroommc/modularui/widget/sizer/IResizeable.java
index f58e8a1b..c86407ce 100644
--- a/src/main/java/com/cleanroommc/modularui/widget/sizer/IResizeable.java
+++ b/src/main/java/com/cleanroommc/modularui/widget/sizer/IResizeable.java
@@ -4,14 +4,60 @@
 
 public interface IResizeable {
 
-    void apply(IGuiElement guiElement);
+    void initResizing();
 
-    void postApply(IGuiElement guiElement);
+    boolean resize(IGuiElement guiElement);
+
+    boolean postResize(IGuiElement guiElement);
 
     default void applyPos(IGuiElement guiElement) {
     }
 
-    default boolean isSkip() {
-        return false;
+    Area getArea();
+
+    boolean isXCalculated();
+
+    boolean isYCalculated();
+
+    boolean isWidthCalculated();
+
+    boolean isHeightCalculated();
+
+    default boolean isSizeCalculated(GuiAxis axis) {
+        return axis.isHorizontal() ? isWidthCalculated() : isHeightCalculated();
+    }
+
+    default boolean isPosCalculated(GuiAxis axis) {
+        return axis.isHorizontal() ? isXCalculated() : isYCalculated();
+    }
+
+    default boolean isFullyCalculated() {
+        return isXCalculated() && isYCalculated() && isWidthCalculated() && isHeightCalculated();
+    }
+
+    void setResized(boolean x, boolean y, boolean w, boolean h);
+
+    default void setPosResized(boolean x, boolean y) {
+        setResized(x, y, isWidthCalculated(), isHeightCalculated());
+    }
+
+    default void setSizeResized(boolean w, boolean h) {
+        setResized(isXCalculated(), isYCalculated(), w, h);
+    }
+
+    default void setXResized(boolean v) {
+        setResized(v, isYCalculated(), isWidthCalculated(), isHeightCalculated());
+    }
+
+    default void setYResized(boolean v) {
+        setResized(isXCalculated(), v, isWidthCalculated(), isHeightCalculated());
+    }
+
+    default void setWidthResized(boolean v) {
+        setResized(isXCalculated(), isYCalculated(), v, isHeightCalculated());
+    }
+
+    default void setHeightResized(boolean v) {
+        setResized(isXCalculated(), isYCalculated(), isWidthCalculated(), v);
     }
 }
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/CategoryList.java b/src/main/java/com/cleanroommc/modularui/widgets/CategoryList.java
index 946c7c38..6c72f384 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/CategoryList.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/CategoryList.java
@@ -86,6 +86,7 @@ public void calculateHeightAndLayout(boolean calculateParents) {
             int y = getArea().height;
             for (IWidget widget : getChildren()) {
                 widget.getArea().ry = y;
+                widget.resizer().setYResized(true);
                 y += widget instanceof CategoryList && ((CategoryList) widget).expanded ?
                         ((CategoryList) widget).totalHeight : widget.getArea().height;
             }
@@ -141,6 +142,7 @@ public void layoutWidgets() {
             int y = 0;
             for (IWidget widget : getChildren()) {
                 widget.getArea().ry = y;
+                widget.resizer().setYResized(true);
                 y += widget instanceof CategoryList && ((CategoryList) widget).expanded ?
                         ((CategoryList) widget).totalHeight : widget.getArea().height;
             }
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/CycleButtonWidget.java b/src/main/java/com/cleanroommc/modularui/widgets/CycleButtonWidget.java
index 1fcb4b84..388528b0 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/CycleButtonWidget.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/CycleButtonWidget.java
@@ -2,6 +2,7 @@
 
 import com.cleanroommc.modularui.ModularUI;
 import com.cleanroommc.modularui.ModularUIConfig;
+import com.cleanroommc.modularui.api.ITheme;
 import com.cleanroommc.modularui.api.drawable.IDrawable;
 import com.cleanroommc.modularui.api.drawable.IKey;
 import com.cleanroommc.modularui.api.value.IBoolValue;
@@ -109,6 +110,11 @@ public void setState(int state, boolean setSource) {
         return Result.IGNORE;
     }
 
+    @Override
+    public WidgetTheme getWidgetTheme(ITheme theme) {
+        return theme.getButtonTheme();
+    }
+
     @Override
     public void drawBackground(GuiContext context) {
         WidgetTheme widgetTheme = getWidgetTheme(context.getTheme());
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/ListWidget.java b/src/main/java/com/cleanroommc/modularui/widgets/ListWidget.java
index 69bcd833..27098a19 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/ListWidget.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/ListWidget.java
@@ -62,8 +62,7 @@ public static <T, I extends IWidget, W extends ListWidget<T, I, W>> ListWidget<T
     }
 
     @Override
-    public void resize() {
-        super.resize();
+    public void onResized() {
         if (this.keepScrollBarInArea) return;
         if (this.scrollData.direction == ScrollDirection.VERTICAL) {
             getArea().width += this.scrollData.getScrollbarThickness();
@@ -106,10 +105,18 @@ public void layoutWidgets() {
             if (widget.getFlex() != null && (axis.isVertical() ? widget.getFlex().hasYPos() : widget.getFlex().hasXPos())) {
                 continue;
             }
+            if (axis.isHorizontal() ? !widget.resizer().isWidthCalculated() : !widget.resizer().isHeightCalculated()) {
+                continue;
+            }
             p += Math.max(lastMargin, widget.getArea().getMargin().getStart(axis));
             widget.getArea().setRelativePoint(axis, p);
             p += widget.getArea().getSize(axis);
             lastMargin = widget.getArea().getMargin().getEnd(axis);
+            if (axis.isHorizontal()) {
+                widget.resizer().setXResized(true);
+            } else {
+                widget.resizer().setYResized(true);
+            }
         }
         getScrollData().scrollSize = p + Math.max(lastMargin, getArea().getPadding().getEnd(axis));
     }
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/PagedWidget.java b/src/main/java/com/cleanroommc/modularui/widgets/PagedWidget.java
index 838b9b33..35aa719d 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/PagedWidget.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/PagedWidget.java
@@ -62,14 +62,15 @@ public int getCurrentPageIndex() {
         return this.pages;
     }
 
-    @Override
-    public void resize() {
+    // TODO why is this needed?
+    /*@Override
+    public boolean resize(boolean init) {
         int page = this.currentPageIndex;
         this.currentPageIndex = -1;
-        super.resize();
+        boolean b = super.resize(init);
         this.currentPageIndex = page;
-
-    }
+        return b;
+    }*/
 
     public W addPage(IWidget widget) {
         this.pages.add(widget);
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/PopupMenu.java b/src/main/java/com/cleanroommc/modularui/widgets/PopupMenu.java
index fc6229dd..0ba2034c 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/PopupMenu.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/PopupMenu.java
@@ -14,7 +14,7 @@ public class PopupMenu<W extends PopupMenu<W>> extends Widget<W> {
 
     public PopupMenu(IWidget child) {
         this.menu = new MenuWrapper(child);
-        child.flex().relative(this);
+        child.flex().relative(this.getArea());
         this.menu.setEnabled(false);
         this.children = Collections.singletonList(this.menu);
     }
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/ProgressWidget.java b/src/main/java/com/cleanroommc/modularui/widgets/ProgressWidget.java
index 10328943..fe0c2818 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/ProgressWidget.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/ProgressWidget.java
@@ -44,8 +44,7 @@ public boolean isValidSyncHandler(SyncHandler syncHandler) {
     }
 
     @Override
-    public void resize() {
-        super.resize();
+    public void onResized() {
         if (this.imageSize < 0) {
             this.imageSize = getArea().width;
         }
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/SliderWidget.java b/src/main/java/com/cleanroommc/modularui/widgets/SliderWidget.java
index a2ddd68a..5bbc4ef8 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/SliderWidget.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/SliderWidget.java
@@ -99,8 +99,7 @@ public void draw(GuiContext context) {
     }
 
     @Override
-    public void resize() {
-        super.resize();
+    public void onResized() {
         float sw = this.sliderWidth.getValue();
         if (this.sliderWidth.isRelative()) sw *= getArea().width;
         float sh = this.sliderHeight.getValue();
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/TextWidget.java b/src/main/java/com/cleanroommc/modularui/widgets/TextWidget.java
index 9ba8f0a8..5b071ae5 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/TextWidget.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/TextWidget.java
@@ -9,7 +9,6 @@
 import com.cleanroommc.modularui.utils.Alignment;
 import com.cleanroommc.modularui.widget.Widget;
 import com.cleanroommc.modularui.widget.sizer.Box;
-import com.cleanroommc.modularui.widget.sizer.Flex;
 
 public class TextWidget extends Widget<TextWidget> {
 
@@ -53,10 +52,8 @@ public WidgetTheme getWidgetTheme(ITheme theme) {
         return theme.getWidgetTheme(this.widgetTheme);
     }
 
-    @Override
-    public int getDefaultHeight() {
-        Flex parentFlex = getParent().getFlex();
-        float maxWidth = parentFlex != null && !parentFlex.xAxisDependsOnChildren() ? getParent().getArea().width : Float.MAX_VALUE;
+    private TextRenderer simulate() {
+        float maxWidth = getParent().resizer() != null ? getParent().getArea().width : Float.MAX_VALUE;
         Box padding = getArea().getPadding();
         TextRenderer renderer = TextRenderer.SHARED;
         renderer.setAlignment(Alignment.TopLeft, maxWidth);
@@ -64,20 +61,26 @@ public int getDefaultHeight() {
         renderer.setScale(this.scale);
         renderer.setSimulate(true);
         renderer.draw(this.key.get());
+        return renderer;
+    }
+
+    @Override
+    public int getDefaultHeight() {
+        if (getParent().resizer() != null && !getParent().resizer().isWidthCalculated()) {
+            return -1;
+        }
+        TextRenderer renderer = simulate();
+        Box padding = getArea().getPadding();
         return (int) (renderer.getLastHeight() + padding.vertical() + 0.5f);
     }
 
     @Override
     public int getDefaultWidth() {
-        Flex parentFlex = getParent().getFlex();
-        float maxWidth = parentFlex != null && !parentFlex.xAxisDependsOnChildren() ? getParent().getArea().width : Float.MAX_VALUE;
+        if (getParent().resizer() != null && !getParent().resizer().isWidthCalculated()) {
+            return -1;
+        }
+        TextRenderer renderer = simulate();
         Box padding = getArea().getPadding();
-        TextRenderer renderer = TextRenderer.SHARED;
-        renderer.setAlignment(Alignment.TopLeft, maxWidth);
-        renderer.setPos(padding.left, padding.top);
-        renderer.setScale(this.scale);
-        renderer.setSimulate(true);
-        renderer.draw(this.key.get());
         return (int) (renderer.getLastWidth() + padding.horizontal() + 0.5f);
     }
 
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/layout/Column.java b/src/main/java/com/cleanroommc/modularui/widgets/layout/Column.java
index 8d38bfd0..c783bff7 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/layout/Column.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/layout/Column.java
@@ -20,8 +20,8 @@ public Column() {
 
     @Override
     public void layoutWidgets() {
+        boolean hasHeight = resizer().isHeightCalculated();
         int height = getArea().height;
-        int width = getArea().width;
         Box padding = getArea().getPadding();
 
         int maxWidth = 0;
@@ -41,23 +41,26 @@ public void layoutWidgets() {
             totalHeight += widget.getArea().requestedHeight();
         }
 
-        if (expandedAmount > 0) {
+        if (expandedAmount > 0 && hasHeight) {
             int newHeight = (height - totalHeight - padding.vertical()) / expandedAmount;
             for (IWidget widget : getChildren()) {
                 // exclude self positioned (Y) children
                 if (widget.flex().hasYPos()) continue;
                 if (widget.flex().isExpanded()) {
-                    widget.getArea().h(newHeight);
+                    widget.getArea().height = newHeight;
+                    widget.resizer().setHeightResized(true);
                 }
             }
         }
 
         // calculate start y
         int lastY = 0;
-        if (this.maa == MainAxisAlignment.CENTER) {
-            lastY = (int) (height / 2f - totalHeight / 2f);
-        } else if (this.maa == MainAxisAlignment.END) {
-            lastY = height - totalHeight;
+        if (hasHeight) {
+            if (this.maa == MainAxisAlignment.CENTER) {
+                lastY = (int) (height / 2f - totalHeight / 2f);
+            } else if (this.maa == MainAxisAlignment.END) {
+                lastY = height - totalHeight;
+            }
         }
         lastY = Math.max(lastY, padding.top) - getArea().getMargin().top;
 
@@ -65,25 +68,40 @@ public void layoutWidgets() {
             // exclude self positioned (Y) children
             if (widget.flex().hasYPos()) continue;
             Box margin = widget.getArea().getMargin();
-            // don't align auto positioned (X) children in X
-            if (!widget.flex().hasXPos()) {
-                int x = 0;
-                if (this.caa == CrossAxisAlignment.CENTER) {
-                    x = (int) (width / 2f - widget.getArea().requestedWidth() / 2f);
-                } else if (this.caa == CrossAxisAlignment.END) {
-                    x = width - widget.getArea().requestedWidth();
-                }
-                x = Math.max(x, padding.left + margin.left);
-                widget.getArea().rx = x;
-            }
 
             // set calculated relative Y pos and set bottom margin for next widget
             widget.getArea().ry = lastY + margin.top;
 
             lastY += widget.getArea().requestedHeight();
-            if (this.maa == MainAxisAlignment.SPACE_BETWEEN) {
+            if (hasHeight && this.maa == MainAxisAlignment.SPACE_BETWEEN) {
                 lastY += (height - totalHeight) / (getChildren().size() - 1);
             }
+            widget.resizer().setYResized(true);
+        }
+    }
+
+    @Override
+    public void postLayoutWidgets() {
+        int width = getArea().width;
+        Box padding = getArea().getPadding();
+        boolean hasWidth = resizer().isWidthCalculated();
+        for (IWidget widget : getChildren()) {
+            // exclude self positioned (Y) children
+            if (widget.flex().hasYPos()) continue;
+            Box margin = widget.getArea().getMargin();
+            // don't align auto positioned (X) children in X
+            if (!widget.flex().hasXPos() && widget.resizer().isWidthCalculated()) {
+                int x = padding.left + margin.left;
+                if (hasWidth) {
+                    if (this.caa == CrossAxisAlignment.CENTER) {
+                        x = (int) (width / 2f - widget.getArea().width / 2f);
+                    } else if (this.caa == CrossAxisAlignment.END) {
+                        x = width - widget.getArea().width - padding.right - margin.left;
+                    }
+                }
+                widget.getArea().rx = x;
+                widget.resizer().setXResized(true);
+            }
         }
     }
 
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/layout/Grid.java b/src/main/java/com/cleanroommc/modularui/widgets/layout/Grid.java
index 212247e3..08e82986 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/layout/Grid.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/layout/Grid.java
@@ -83,6 +83,7 @@ public void layoutWidgets() {
                 if (child != null) {
                     child.getArea().rx = (int) (x + width * 0.5 - child.getArea().width * 0.5);
                     child.getArea().ry = (int) (y + height * 0.5 - child.getArea().height * 0.5);
+                    child.resizer().setPosResized(true, true);
                 }
                 x += width;
             }
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/layout/OrganizedPanel.java b/src/main/java/com/cleanroommc/modularui/widgets/layout/OrganizedPanel.java
index ed3bab95..5924f576 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/layout/OrganizedPanel.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/layout/OrganizedPanel.java
@@ -64,7 +64,7 @@ public ParentWidget<?> getBody() {
     }
 
     @Override
-    public void resize() {
+    public void beforeResize() {
         int top = 0;
         int bot = 0;
         this.body.flex().reset();
@@ -91,7 +91,6 @@ public void resize() {
             this.rightSide.right(0).width(this.rightSideWidth).top(top).bottom(bot);
             this.body.right(this.rightSideWidth);
         }
-        super.resize();
     }
 
     public OrganizedPanel header(IWidget widget) {
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/layout/Row.java b/src/main/java/com/cleanroommc/modularui/widgets/layout/Row.java
index b8766b56..f7d06417 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/layout/Row.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/layout/Row.java
@@ -20,8 +20,8 @@ public Row() {
 
     @Override
     public void layoutWidgets() {
+        boolean hasWidth = resizer().isWidthCalculated();
         int width = getArea().width;
-        int height = getArea().height;
         Box padding = getArea().getPadding();
 
         int maxHeight = 0;
@@ -40,23 +40,26 @@ public void layoutWidgets() {
             totalWidth += widget.getArea().requestedWidth();
         }
 
-        if (expandedAmount > 0) {
+        if (expandedAmount > 0 && hasWidth) {
             int newWidth = (width - totalWidth - padding.horizontal()) / expandedAmount;
             for (IWidget widget : getChildren()) {
                 // exclude self positioned (X) children
                 if (widget.flex().hasXPos()) continue;
                 if (widget.flex().isExpanded()) {
-                    widget.getArea().w(newWidth);
+                    widget.getArea().width = newWidth;
+                    widget.resizer().setWidthResized(true);
                 }
             }
         }
 
         // calculate start y
         int lastX = 0;
-        if (this.maa == MainAxisAlignment.CENTER) {
-            lastX = (int) (width / 2f - totalWidth / 2f);
-        } else if (this.maa == MainAxisAlignment.END) {
-            lastX = width - totalWidth;
+        if (hasWidth) {
+            if (this.maa == MainAxisAlignment.CENTER) {
+                lastX = (int) (width / 2f - totalWidth / 2f);
+            } else if (this.maa == MainAxisAlignment.END) {
+                lastX = width - totalWidth;
+            }
         }
         lastX = Math.max(lastX, padding.left) - getArea().getMargin().left;
 
@@ -64,28 +67,43 @@ public void layoutWidgets() {
             // exclude self positioned (X) children
             if (widget.flex().hasXPos()) continue;
             Box margin = widget.getArea().getMargin();
-            // don't align auto positioned (Y) children in Y
-            if (!widget.flex().hasYPos()) {
-                int y = 0;
-                if (this.caa == CrossAxisAlignment.CENTER) {
-                    y = (int) (height / 2f - widget.getArea().requestedHeight() / 2f);
-                } else if (this.caa == CrossAxisAlignment.END) {
-                    y = height - widget.getArea().requestedHeight();
-                }
-                y = Math.max(y, padding.top);
-                widget.getArea().ry = y;
-            }
 
             // set calculated relative Y pos and set bottom margin for next widget
             widget.getArea().rx = lastX + margin.left;
+            widget.resizer().setXResized(true);
 
             lastX += widget.getArea().requestedWidth();
-            if (this.maa == MainAxisAlignment.SPACE_BETWEEN) {
+            if (hasWidth && this.maa == MainAxisAlignment.SPACE_BETWEEN) {
                 lastX += (width - totalWidth) / (getChildren().size() - 1);
             }
         }
     }
 
+    @Override
+    public void postLayoutWidgets() {
+        int height = getArea().height;
+        Box padding = getArea().getPadding();
+        boolean hasHeight = resizer().isWidthCalculated();
+        for (IWidget widget : getChildren()) {
+            // exclude self positioned (X) children
+            if (widget.flex().hasXPos()) continue;
+            Box margin = widget.getArea().getMargin();
+            // don't align auto positioned (Y) children in Y
+            if (!widget.flex().hasYPos()) {
+                int y = margin.top + padding.top;
+                if (hasHeight) {
+                    if (this.caa == CrossAxisAlignment.CENTER) {
+                        y = (int) (height / 2f - widget.getArea().height / 2f);
+                    } else if (this.caa == CrossAxisAlignment.END) {
+                        y = height - widget.getArea().height - margin.bottom - padding.bottom;
+                    }
+                }
+                widget.getArea().ry = y;
+                widget.resizer().setYResized(true);
+            }
+        }
+    }
+
     public Row crossAxisAlignment(CrossAxisAlignment caa) {
         this.caa = caa;
         return this;
diff --git a/src/main/java/com/cleanroommc/modularui/widgets/slot/ModularSlot.java b/src/main/java/com/cleanroommc/modularui/widgets/slot/ModularSlot.java
index b1a55b94..c1d4aa40 100644
--- a/src/main/java/com/cleanroommc/modularui/widgets/slot/ModularSlot.java
+++ b/src/main/java/com/cleanroommc/modularui/widgets/slot/ModularSlot.java
@@ -67,6 +67,12 @@ public void onSlotChanged() {
         this.changeListener.accept(getStack());
     }
 
+    @Override
+    public void putStack(@NotNull ItemStack stack) {
+        if (ItemStack.areItemStacksEqual(stack, getStack())) return;
+        super.putStack(stack);
+    }
+
     @Nullable
     @SideOnly(Side.CLIENT)
     @Override