Dreamweaver display bug?

Whenever a panel in the interface becomes inactive (greyed out), the GUI lags for a second while it re-draws the greyed out panel. For example, if I’m working on an HTML document, the Properties panel is active. When I switch to a CSS document, it becomes greyed out, and takes a second or two for the panel to redraw in grey. Really annoying.

This only started happening on my new computer (Athlon 3500+, 2gb RAM, Geforce 6600GT PCIe), so I think it has something to do with the video card.

Any ideas? I’m using Dreamweaver 7.0.1