Minor drawing problem on 9.99-4

Hi,

I'm seeing a minor drawing problem on WinXP SP2. If I do the following 
on the tool panel bar.

Close up the Attributes and Apply class elements. Then open Apply class, 
then open Attributes. There's a spurious divider being drawn across the 
text for the Style element. Dragging another window over the 'divider' 
causes repainting and it's gone.

I'm running this on a Dell M70 laptop with an NVidia Quadro FX Go 1400 
display adapter. The drivers probably aren't the most recent, but I'm 
reluctant to install anything newer for such a trivial problem...

regards

Steve