Dragging a translucent window is annoyingly jumpy

I have a translucent window with lot of shapes and I have red border on the top. Clicking the red border and dragging the mouse will drag the window to the mouse location. I tried this on a few machines and the movement of the stage is very jumpy and sometimes, the window keeps jumping in all directions until I release the mouse. This is very prominent on many configurations.

But this is not reproducible on all machines but only on some machines. For ex, I reproduced it prominently and consistantly on WinXP SP2 with ATI Radeon 9600, WinXP SP2 - Intel Onboard (P3 systems) but this is seen rarely on my WinXP-SP3 with Nvidia GeForce 7600 (512 MB VRAM). I don't really know the connection though.

I reproduced it with JavaFX SDK b55 (reproducible atleast since b53) with 6u11.

To reproduce the bug, run the attached test. Click on the red border and start dragging the window in different directions and do it fast as well as slow. If the window suddenly keeps jumping indefinitely until you release the mouse, the bug is reproduced.