修复bug

assets/editor/script/SelectMapPanel.ts

@@ -81,6 +81,7 @@ export class SelectMapPanel extends Component {
         let count = allMapKeys.length;
         for(let i = 0; i < count; i++){
             let item = this._items[i]
+            if(!item || !item.isValid) continue
             item.getComponent(MapItem).setSelectMap(false)
         }
     }