User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b12) Gecko/20100101 Firefox/4.0b12 Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b12) Gecko/20100101 Firefox/4.0b12 The vertically shaded background of an Aero window border is shifting down when mouse-hovering over a link and the Add-ons toolbar is activated. Reproducible: Always Steps to Reproduce: 1.Have one of the Win7 Aero themes is activated. One with semi-transparent window frames. 2. Start Firefox and go to any site. 3. Activate Add-on toolbar. 4. Hover over any link in page. Actual Results: the shades shifts downwards on the left and right window border. The shift happens when the link address is displayed above the add-on toolbar. Expected Results: That the window frame isn't affected
I can confirm this. I've also seen it with the add-on bar hidden. To reproduce your description, I activated the add-on bar and the window frame effect was still there. But since I have hidden the add-on bar again, the effect is gone. Even after a Firefox restart (and the still-hidden add-on bar, this is new in 4.0b12) there was no more effect to see. This frame effect is irritating a lot more than the appearing and disappearing of the "status bar" when hovering a link, at least when the background (desktop or other windows behind) is relatively dark in that area.
See bug 633282