Issue in tools 10.1'pre2

Hi,
I found a small issue in the tools bar, a UI glitch.

Opening and closing the Style artifact sometimes leave an unpainted area.
The unpainted areas coincide with the dropdows: theme, font, font size.
See the attached image.

The defect shows sometimes, try:
+ open Elements
+ open Style
+ close Elements
+ close Style

This is 10.1-pre2 in Windows XP Pro 2002 SP2.

Saludos!
--
Juan Lanus