diff --git a/packages/designer/src/builtin-simulator/host.ts b/packages/designer/src/builtin-simulator/host.ts
index d71715cc6..5c9c2ae60 100644
--- a/packages/designer/src/builtin-simulator/host.ts
+++ b/packages/designer/src/builtin-simulator/host.ts
@@ -826,7 +826,7 @@ export class BuiltinSimulatorHost implements ISimulatorHost<BuiltinSimulatorProp
       event: e,
     };
 
-    if (e.dragObject.type === 'node' && e.dragObject.nodes[0].getPrototype().isModal()) {
+    if (e.dragObject.type === 'node' && e.dragObject.nodes[0]?.getPrototype()?.isModal()) {
       return this.designer.createLocation({
         target: this.document.rootNode,
         detail: {
diff --git a/packages/plugin-outline-pane/src/views/tree-branches.tsx b/packages/plugin-outline-pane/src/views/tree-branches.tsx
index d3418277e..879d50fda 100644
--- a/packages/plugin-outline-pane/src/views/tree-branches.tsx
+++ b/packages/plugin-outline-pane/src/views/tree-branches.tsx
@@ -71,7 +71,7 @@ class TreeNodeChildren extends Component<{
       />
     );
     treeNode.children?.forEach((child, index) => {
-      const childIsModal = child.node.getPrototype().isModal();
+      const childIsModal = child.node.getPrototype()?.isModal() || false;
       if (isModal != childIsModal) {
         return;
       }