update demo

Author: jogibear9988

package.json

@@ -31,7 +31,7 @@
     "@node-projects/gitgraph-js": "^2.1.0",
     "@node-projects/lean-he-esm": "^3.3.0",
     "@node-projects/node-html-parser-esm": "^6.2.0",
-    "@node-projects/web-component-designer": "^0.1.211",
+    "@node-projects/web-component-designer": "^0.1.212",
     "@node-projects/web-component-designer-codeview-monaco": "^0.1.27",
     "@node-projects/web-component-designer-htmlparserservice-nodehtmlparser": "^0.1.11",
     "@node-projects/web-component-designer-stylesheetservice-css-tools": "^0.1.9",

src/CommandHandling.ts

@@ -116,7 +116,7 @@ export class CommandHandling {
       } else {
         this.handleCommand(buttons, null);
       }
-      const target: DocumentContainer = <DocumentContainer>this.dockManager.activeDocument.resolvedElementContent;
+      const target: DocumentContainer = <DocumentContainer>this.dockManager.activeDocument?.resolvedElementContent;
       if (target) {
         const undoCount = target.instanceServiceContainer.undoService.undoCount;
         const redoCount = target.instanceServiceContainer.undoService.redoCount;