初始化状态框显示状态.

src/UI/Store/DownPanelStore.ts

@@ -21,7 +21,7 @@ function PointToString(pt: Vector3): string
  */
 export class DownPanelStore
 {
-    @observable m_MousePostionPrompt: string;
+    @observable m_MousePostionPrompt: string = "0,0,0";
     @observable useDynInput: boolean = true;
     @observable showToolBar: boolean = true;
     @observable useDynSnap: boolean = true;