diff --git a/inception/inception-brat-editor/src/main/ts/src/BratEditor.ts b/inception/inception-brat-editor/src/main/ts/src/BratEditor.ts
index 4cbbff2a2e8..3cffb830ce1 100644
--- a/inception/inception-brat-editor/src/main/ts/src/BratEditor.ts
+++ b/inception/inception-brat-editor/src/main/ts/src/BratEditor.ts
@@ -41,6 +41,15 @@ export class BratEditor implements AnnotationEditor {
     element.dispatcher = this.dispatcher
     element.visualizer = this.visualizer
 
+    // Ensure that the visualizer is resized when the container element size changes, e.g. when
+    // the sidebars are opened or closed.
+    if (element.parentElement) {
+      new ResizeObserver(() => {
+        console.log(`resize: ${element.id} ${element.clientWidth} ${element.clientHeight}`)
+        this.dispatcher.post('resize')
+      }).observe(element.parentElement)
+    }
+
     this.resizer = new ResizeManager(this.dispatcher, this.visualizer, ajax)
   }
 
diff --git a/inception/inception-brat-editor/src/main/ts/src/visualizer_ui/VisualizerUI.ts b/inception/inception-brat-editor/src/main/ts/src/visualizer_ui/VisualizerUI.ts
index 837aa5b722e..01e083eb9c5 100644
--- a/inception/inception-brat-editor/src/main/ts/src/visualizer_ui/VisualizerUI.ts
+++ b/inception/inception-brat-editor/src/main/ts/src/visualizer_ui/VisualizerUI.ts
@@ -447,7 +447,7 @@ export class VisualizerUI {
 
   resizerTimeout: number
   onResize (evt: Event) {
-    if (evt.target === window) {
+    if (!evt || evt.target === window) {
       clearTimeout(this.resizerTimeout)
       this.resizerTimeout = setTimeout(() => this.dispatcher.post('rerender'), 300)
     }
diff --git a/inception/inception-ui-annotation/src/main/java/de/tudarmstadt/ukp/clarin/webanno/ui/annotation/sidebar/SidebarTabbedPanel.java b/inception/inception-ui-annotation/src/main/java/de/tudarmstadt/ukp/clarin/webanno/ui/annotation/sidebar/SidebarTabbedPanel.java
index 9f5ed3d90bd..d5127590f9c 100644
--- a/inception/inception-ui-annotation/src/main/java/de/tudarmstadt/ukp/clarin/webanno/ui/annotation/sidebar/SidebarTabbedPanel.java
+++ b/inception/inception-ui-annotation/src/main/java/de/tudarmstadt/ukp/clarin/webanno/ui/annotation/sidebar/SidebarTabbedPanel.java
@@ -82,7 +82,7 @@ private void showHideAction(AjaxRequestTarget aTarget)
     {
         expanded = !expanded;
         saveSidebarState();
-        WicketUtil.refreshPage(aTarget, getPage());
+        aTarget.add(findParent(SidebarPanel.class));
     }
 
     public boolean isExpanded()