diff --git a/packages/blockly/core/dragging/block_drag_strategy.ts b/packages/blockly/core/dragging/block_drag_strategy.ts
index 3ed6fbead18..514fb273a25 100644
--- a/packages/blockly/core/dragging/block_drag_strategy.ts
+++ b/packages/blockly/core/dragging/block_drag_strategy.ts
@@ -241,6 +241,7 @@ export class BlockDragStrategy implements IDragStrategy {
             recordUndo: true,
           },
         ) as BlockSvg;
+        newBlock.setDragging(true);
         eventUtils.setRecordUndo(false);
         newBlock.render();
         this.positionNewBlock(this.block, newBlock);
diff --git a/packages/blockly/core/dropdowndiv.ts b/packages/blockly/core/dropdowndiv.ts
index 76876d58c26..b129ead29d9 100644
--- a/packages/blockly/core/dropdowndiv.ts
+++ b/packages/blockly/core/dropdowndiv.ts
@@ -147,7 +147,10 @@ export function createDom() {
     content,
     'keydown',
     null,
-    common.globalShortcutHandler,
+    (e: KeyboardEvent) => {
+      common.globalShortcutHandler(e);
+      e.stopPropagation();
+    },
   );
 
   arrow = document.createElement('div');
diff --git a/packages/blockly/core/widgetdiv.ts b/packages/blockly/core/widgetdiv.ts
index 05b3db8bed0..d76710cb0dd 100644
--- a/packages/blockly/core/widgetdiv.ts
+++ b/packages/blockly/core/widgetdiv.ts
@@ -102,7 +102,10 @@ export function createDom() {
     containerDiv,
     'keydown',
     null,
-    common.globalShortcutHandler,
+    (e: KeyboardEvent) => {
+      common.globalShortcutHandler(e);
+      e.stopPropagation();
+    },
   );
 
   container.appendChild(containerDiv);
diff --git a/packages/blockly/tests/mocha/shortcut_items_test.js b/packages/blockly/tests/mocha/shortcut_items_test.js
index 3b46e096dda..d80147c0863 100644
--- a/packages/blockly/tests/mocha/shortcut_items_test.js
+++ b/packages/blockly/tests/mocha/shortcut_items_test.js
@@ -1885,6 +1885,22 @@ suite('Keyboard Shortcut Items', function () {
       this.workspace.getInjectionDiv().dispatchEvent(event);
       assert.equal(this.workspace.getTopComments().length, 1);
     });
+
+    test('Is idempotent when a contextual menu is open', function () {
+      const comment = this.workspace.newComment();
+      comment.setText('Hello');
+      Blockly.getFocusManager().focusNode(comment);
+      comment.showContextMenu();
+      assert.equal(this.workspace.getTopComments().length, 1);
+      const event = createKeyDownEvent(Blockly.utils.KeyCodes.D);
+      // The WidgetDiv (used by the dropdown menu) registers the global shortcut
+      // handler for its own div, since it may live outside of the injection
+      // div. Ensure that it also prevents event bubbling to the main shortcut
+      // handler, which could cause shortcuts like Duplicate to be invoked
+      // multiple times from one keypress. See #10250.
+      Blockly.WidgetDiv.getDiv().dispatchEvent(event);
+      assert.equal(this.workspace.getTopComments().length, 2);
+    });
   });
 
   suite('Clean up workspace (C)', function () {
diff --git a/packages/blockly/tests/mocha/test_helpers/user_input.js b/packages/blockly/tests/mocha/test_helpers/user_input.js
index 709955af7db..b342631c9c2 100644
--- a/packages/blockly/tests/mocha/test_helpers/user_input.js
+++ b/packages/blockly/tests/mocha/test_helpers/user_input.js
@@ -39,6 +39,7 @@ export function dispatchPointerEvent(target, type, properties) {
 export function createKeyDownEvent(keyCode, modifiers) {
   const event = {
     keyCode: keyCode,
+    bubbles: true,
   };
   if (modifiers && modifiers.length > 0) {
     event.altKey = modifiers.includes(KeyCodes.ALT);