Windows 2000 includes a "shadowed cursor" feature, which paints a shadow underneath the mouse cursor. This is enabled by default.

It appears that this feature is interfering with some of the DirectDraw work that has happened for Merlin. Under certain conditions, the cursor will fail to be repainted over, and "sticks" to the underlying window.

I have never observed this with native applications.

To reproduce:
-bring up SwingSet2 w/ merlin
-bring up the Internal Frames demo
-drag the "factory" internal frame back and forth across the right edge of the SwingSet window

Extra mouse cursors build up on the factory internal frame.

(For what it's worth, this is also reproducible with the mouse wheel while scrolling horizontally. But Swing/MouseWheel is not yet integrated into Merlin).

It is important to provide a fix for this bug to avoid having to work around it by turning off DirectDraw. A lot of work is going into accelerating Swing using VolatileImage and DDraw, and it would be a real shame if the common-case Win2k user wasn't able to take advatage of it.

brent.christian@eng 2000-08-14