自定义popup在屏幕下方会有一块无法遮盖的区域

onWindowStageCreate(windowStage: window.WindowStage): void {  
  ...............  
  let windowClass: window.Window = windowStage.getMainWindowSync(); // 获取应用主窗口  
  // 1. 设置窗口全屏  
  let isLayoutFullScreen = true;  
  windowClass.setWindowLayoutFullScreen(isLayoutFullScreen)  
}