Steps to reproduce :
- Run the attached test case
- Place the scrollbar thumb in the downmost position.
- Click on a location close to thumb, between thumb and up arrow key
- Drag the Mouse upwards in the mouse pressed condition
- You would notice that the thumb instead of following the mouse, will continue to move in the opposite direction(downwards).
This happens only if you are pressing the mouse initially very close to
the thumb.
Above behaviour is intermittent.
This behaviour happens both in case of vertical & horizontal scrollbars.