diff --git a/src/actions/arrow_navigation.ts b/src/actions/arrow_navigation.ts
index e0eef938..31955884 100644
--- a/src/actions/arrow_navigation.ts
+++ b/src/actions/arrow_navigation.ts
@@ -69,11 +69,17 @@ export class ArrowNavigation {
           }
           return isHandled;
         case Constants.STATE.TOOLBOX:
-          // @ts-expect-error private method
-          isHandled = toolbox && toolbox.selectChild();
-          if (!isHandled && flyout) {
-            Blockly.getFocusManager().focusTree(flyout.getWorkspace());
-            this.navigation.defaultFlyoutCursorIfNeeded(workspace);
+          if (toolbox) {
+            const selectedItem = toolbox.getSelectedItem();
+            // Don't auto-expand collapsible items. 'Enter' should be used.
+            if (selectedItem && !selectedItem.isCollapsible()) {
+              // @ts-expect-error private method
+              isHandled = toolbox.selectChild();
+            }
+            if (!isHandled && flyout) {
+              Blockly.getFocusManager().focusTree(flyout.getWorkspace());
+              this.navigation.defaultFlyoutCursorIfNeeded(workspace);
+            }
           }
           return true;
         default:
diff --git a/src/actions/enter.ts b/src/actions/enter.ts
index a9e069a9..ef1a41ff 100644
--- a/src/actions/enter.ts
+++ b/src/actions/enter.ts
@@ -19,7 +19,7 @@ import {
   FocusableTreeTraverser,
 } from 'blockly/core';
 
-import type {Block} from 'blockly/core';
+import type {Block, ICollapsibleToolboxItem, Toolbox} from 'blockly/core';
 
 import * as Constants from '../constants';
 import type {Navigation} from '../navigation';
@@ -62,6 +62,8 @@ export class EnterAction {
         let flyoutCursor;
         let curNode;
 
+        const toolbox = workspace.getToolbox() as Toolbox;
+
         switch (this.navigation.getState(workspace)) {
           case Constants.STATE.WORKSPACE:
             this.handleEnterForWS(workspace);
@@ -77,7 +79,16 @@ export class EnterAction {
             } else if (curNode instanceof FlyoutButton) {
               this.triggerButtonCallback(workspace);
             }
-
+            return true;
+          case Constants.STATE.TOOLBOX:
+            if (toolbox) {
+              const selectedItem = toolbox.getSelectedItem();
+              // Only navigate for collapsible items.
+              if (selectedItem && selectedItem.isCollapsible()) {
+                (selectedItem as ICollapsibleToolboxItem).toggleExpanded();
+                toolbox.refreshSelection();
+              }
+            }
             return true;
           default:
             return false;