diff --git a/src/main/java/featurecat/lizzie/Lizzie.java b/src/main/java/featurecat/lizzie/Lizzie.java
index 516c42e7..5eddad80 100644
--- a/src/main/java/featurecat/lizzie/Lizzie.java
+++ b/src/main/java/featurecat/lizzie/Lizzie.java
@@ -94,7 +94,7 @@ public static void shutdown() {
     if (config.config.getJSONObject("ui").getBoolean("confirm-exit")) {
       int ret =
           JOptionPane.showConfirmDialog(
-              null, "Do you want to save this SGF?", "Save SGF?", JOptionPane.OK_CANCEL_OPTION);
+              frame, "Do you want to save this SGF?", "Save SGF?", JOptionPane.OK_CANCEL_OPTION);
       if (ret == JOptionPane.OK_OPTION) {
         frame.saveFile();
       }
diff --git a/src/main/java/featurecat/lizzie/analysis/YaZenGtp.java b/src/main/java/featurecat/lizzie/analysis/YaZenGtp.java
index c7f14a05..b03e0aab 100644
--- a/src/main/java/featurecat/lizzie/analysis/YaZenGtp.java
+++ b/src/main/java/featurecat/lizzie/analysis/YaZenGtp.java
@@ -53,7 +53,7 @@ public void startEngine(String engineCommand, int index) {
       process = processBuilder.start();
     } catch (IOException e) {
       // TODO Auto-generated catch block
-      Utils.showMessageDialog(null, resourceBundle.getString("YaZenGtp.nofile"));
+      Utils.showMessageDialog(Lizzie.frame, resourceBundle.getString("YaZenGtp.nofile"));
       return;
     }
     initializeStreams();
@@ -99,7 +99,7 @@ private void parseLine(String line) {
       }
 
       if (line.startsWith("Throw")) {
-        Utils.showMessageDialog(null, resourceBundle.getString("YaZenGtp.nofile"));
+        Utils.showMessageDialog(Lizzie.frame, resourceBundle.getString("YaZenGtp.nofile"));
         shutdown();
       }
       if (line.startsWith(" ")) {
diff --git a/src/main/java/featurecat/lizzie/gui/BoardPane.java b/src/main/java/featurecat/lizzie/gui/BoardPane.java
index 282145aa..cdbfdb04 100644
--- a/src/main/java/featurecat/lizzie/gui/BoardPane.java
+++ b/src/main/java/featurecat/lizzie/gui/BoardPane.java
@@ -531,14 +531,14 @@ public void replayBranch(boolean generateGif) {
       chooser.setAcceptAllFileFilterUsed(false);
       chooser.setFileFilter(filter);
       chooser.setMultiSelectionEnabled(false);
-      int result = chooser.showSaveDialog(null);
+      int result = chooser.showSaveDialog(Lizzie.frame);
       if (result == JFileChooser.APPROVE_OPTION) {
         File file = chooser.getSelectedFile();
         filesystem.put("last-image-folder", file.getParent());
         if (file.exists()) {
           int ret =
               JOptionPane.showConfirmDialog(
-                  null,
+                  Lizzie.frame,
                   resourceBundle.getString("LizzieFrame.prompt.fileExists"),
                   "Warning",
                   JOptionPane.OK_CANCEL_OPTION);
@@ -620,7 +620,7 @@ public void saveImage() {
     chooser.addChoosableFileFilter(filter3);
     chooser.addChoosableFileFilter(filter4);
     chooser.setMultiSelectionEnabled(false);
-    int result = chooser.showSaveDialog(null);
+    int result = chooser.showSaveDialog(Lizzie.frame);
     if (result == JFileChooser.APPROVE_OPTION) {
       File file = chooser.getSelectedFile();
       filesystem.put("last-image-folder", file.getParent());
@@ -636,7 +636,7 @@ public void saveImage() {
       if (file.exists()) {
         int ret =
             JOptionPane.showConfirmDialog(
-                null,
+                Lizzie.frame,
                 resourceBundle.getString("LizzieFrame.prompt.fileExists"),
                 "Warning",
                 JOptionPane.OK_CANCEL_OPTION);
diff --git a/src/main/java/featurecat/lizzie/gui/LizzieDialog.java b/src/main/java/featurecat/lizzie/gui/LizzieDialog.java
index 51abd2e5..502e5417 100644
--- a/src/main/java/featurecat/lizzie/gui/LizzieDialog.java
+++ b/src/main/java/featurecat/lizzie/gui/LizzieDialog.java
@@ -1,5 +1,6 @@
 package featurecat.lizzie.gui;
 
+import featurecat.lizzie.Lizzie;
 import java.awt.Dialog;
 import java.awt.Frame;
 import java.awt.Window;
@@ -12,7 +13,7 @@ public class LizzieDialog extends JDialog {
   private String osName;
 
   public LizzieDialog() {
-    super();
+    super(Lizzie.frame); // Set owner for dual monitors. (#885)
     setOsName();
   }
 
diff --git a/src/main/java/featurecat/lizzie/gui/MainFrame.java b/src/main/java/featurecat/lizzie/gui/MainFrame.java
index 45058e35..256acceb 100644
--- a/src/main/java/featurecat/lizzie/gui/MainFrame.java
+++ b/src/main/java/featurecat/lizzie/gui/MainFrame.java
@@ -228,7 +228,7 @@ public void editComment() {
     textArea.setSize(textArea.getPreferredSize().width, textArea.getPreferredSize().height);
     int ret =
         JOptionPane.showConfirmDialog(
-            null, new JScrollPane(textArea), "Comment", JOptionPane.OK_CANCEL_OPTION);
+            this, new JScrollPane(textArea), "Comment", JOptionPane.OK_CANCEL_OPTION);
     if (ret == JOptionPane.OK_OPTION) {
       Lizzie.board.getHistory().getData().comment = textArea.getText();
       refresh();
@@ -396,7 +396,7 @@ public void saveFile() {
     JFileChooser chooser = new JFileChooser(filesystem.getString("last-folder"));
     chooser.setFileFilter(filter);
     chooser.setMultiSelectionEnabled(false);
-    int result = chooser.showSaveDialog(null);
+    int result = chooser.showSaveDialog(this);
     if (result == JFileChooser.APPROVE_OPTION) {
       File file = chooser.getSelectedFile();
       if (!(file.getPath().endsWith(".sgf") || file.getPath().endsWith(".SGF"))) {
@@ -405,7 +405,7 @@ public void saveFile() {
       if (file.exists()) {
         int ret =
             JOptionPane.showConfirmDialog(
-                null,
+                this,
                 resourceBundle.getString("LizzieFrame.prompt.sgfExists"),
                 "Warning",
                 JOptionPane.OK_CANCEL_OPTION);
@@ -420,7 +420,7 @@ public void saveFile() {
         }
       } catch (IOException err) {
         JOptionPane.showConfirmDialog(
-            null,
+            this,
             resourceBundle.getString("LizzieFrame.prompt.failedTosaveFile"),
             "Error",
             JOptionPane.ERROR);
@@ -461,7 +461,7 @@ public void loadFile(File file) {
       }
     } catch (IOException err) {
       JOptionPane.showConfirmDialog(
-          null,
+          this,
           resourceBundle.getString("LizzieFrame.prompt.failedToOpenFile"),
           "Error",
           JOptionPane.ERROR);
diff --git a/src/main/java/featurecat/lizzie/rules/Board.java b/src/main/java/featurecat/lizzie/rules/Board.java
index 603c950d..f08fbc7e 100644
--- a/src/main/java/featurecat/lizzie/rules/Board.java
+++ b/src/main/java/featurecat/lizzie/rules/Board.java
@@ -1075,7 +1075,7 @@ public void deleteMove() {
         // Will delete more than one move, ask for confirmation
         int ret =
             JOptionPane.showConfirmDialog(
-                null,
+                Lizzie.frame,
                 "This will delete all moves and branches after this move",
                 "Delete",
                 JOptionPane.OK_CANCEL_OPTION);
@@ -1395,12 +1395,12 @@ public void toggleAnalysis() {
       analysisMode = false;
     } else {
       if (!getNextMove().isPresent()) {
-        JOptionPane.showMessageDialog(null, "No next move.");
+        JOptionPane.showMessageDialog(Lizzie.frame, "No next move.");
         return;
       }
       String answer =
           JOptionPane.showInputDialog(
-              "# playouts for analysis (e.g. 100 (fast) or 50000 (slow)): ");
+              Lizzie.frame, "# playouts for analysis (e.g. 100 (fast) or 50000 (slow)): ");
       try {
         playoutsAnalysis = Integer.parseInt(answer);
       } catch (NumberFormatException err) {