gwt中的弹出面板

当鼠标输入时，弹出面板将如何工作；当鼠标离开时，弹出面板将隐藏；当光标在弹出面板内移动时，弹出面板将停留在弹出面板上。

我正在这样做，但弹出面板没有停留是有问题的……你知道吗

  Event.addNativePreviewHandler(new NativePreviewHandler() {
      public void onPreviewNativeEvent(final NativePreviewEvent event) {
        final int eventType = event.getTypeInt();
        switch (eventType) {

          case Event.ONMOUSEOUT:
          {
                        System.out.println("hello");
                        popup.setVisible(false);
           break;
          }
          case Event.ONMOUSEOVER:
          {
              l1.addMouseOverHandler(new MouseOverHandler()
              {
                  public void onMouseOver(MouseOverEvent event)
                  {
              popup.show();
              popup.setPopupPositionAndShow(new PopupPanel.PositionCallback() 
                {
                    public void setPosition(int offsetWidth, int offsetHeight) 
                        {
                            int left = (Window.getClientWidth() - offsetWidth) / 24;
                            int top = (Window.getClientHeight() - offsetHeight) / 5;
                            popup.setPopupPosition(left, top);
                        }
                });
              MouseOutHandler handler1=new MouseOutHandler()
                {
                    public void onMouseOut(MouseOutEvent event)
                    {
                        System.out.println("welcome2");
                        popup.setVisible(false);

                    }
                };
                popup.addHandler(handler1,MouseOutEvent.getType());
               popup.sinkEvents(Event.ONMOUSEOUT); 
               event.preventDefault();
                  }
              });
            break;
          }
          default: 

        }
      }
    });

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例如，我们有上面的标签。当我们将光标移到上面时，将显示弹出窗口，当鼠标移出时，它将隐藏。当光标位于弹出窗口内时，它将停留。