🚀 go-pugleaf

Hello,

I've noticed some curious behavior with a JScrollPane component in my
program, and I hope someone can help me understand it.

I have a custom class, "MyScrollableComponent", which extends JComponent,
and implements Scrollable, MouseListener, and MouseMotionListener.  My
intent is to contain a BufferedImage within this class, load in a jpeg, and
then add it (an instance of MyScrollableComponent) to the viewport of a
JScrollPane.  It all works fine, but listening for mouse motion events is a
little strange.

If I do this, e.g., in the constructor of my JFrame class (which contains
the JScrollPane):

...
myScrollPane.setViewportView(myScrollableComponent);
myScrollPane.addMouseMotionListener(myScrollableComponent);
...

Then the mouseMoved() function is called in myScrollableComponent - UNTIL I
load an image into myScrollableComponent.


However, if instead I add myScrollableComponent as a mouse motion listener
to ITSELF, e.g., in the constructor of myScrollableComponent,

....
addMouseMotionListener(this);
....


Then the opposite happens.  I get no mouse activity until I load an image.

Can someone help me understand this interesting behavior of JScrollPane?

Thanks.

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