画布新增图层撤回问题

src/component/Canvas/CanvasEditor/commands/LayerCommands.js

@@ -70,7 +70,7 @@ export class AddLayerCommand extends Command {
 
   undo() {
     // 从图层列表删除该图层
-    this.layers.value = this.beforeLayers;
+    this.layers.value = [...this.beforeLayers];
 
     // 恢复原活动图层
     this.activeLayerId.value = this.oldActiveLayerId;