当组件设置为可见时，为什么MouseMotionListener的mouseMoved方法会生成事件？

Question

I have added MouseMotionListener to Component, about 5 parents above. When I set main JWindow setVisible(true); , then immediately mouseMoved(MouseEvent e) method generates one event. After that everything works fine. Could it be some bug?

Some solution is possible:

public class SomeClass extends Component{

   private int mouseMoveCount;

   public SomeClass(){

   addMouseMotionListener(new MouseMotionAdapter() {
                @Override
                public void mouseMoved(MouseEvent e) {

                    if (mouseMoveCount > 1) {
                        //Do something
                        mouseMoveCount = 0;
                    }
                    mouseMoveCount++;
                }
            });
    }
}

jWindow.setVisible(true); is done after validate(); and pack(); . Mouse, of course sits in place, I do not touch it :) But it still generates one event..

Answer 1

Finally found the reason - before setting to visible, I was dispatching MouseEvent ( MouseEvent.MOUSE_ENTERED ) to Component MouseListener - it was a mistake. But interesting to know, that dispatching this event also triggered mouseMoved .