User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:2.0b5pre) Gecko/20100819 Minefield/4.0b5pre Firefox/4.0b4pre Build Identifier: Don't know if its hardware related, but this looks like a new bug in the last day or two. Reproducible: Always Steps to Reproduce: Turn on DW, D2D Have Aero Theme enabled switch tabs, should see a grey ui paint in the bottom of the content area just above the status bar. it looks to be the same height as my toolbars. Actual Results: grey bar on every tab switch Expected Results: no grey bar, content should draw down to window edge sans status bar looks like a new regression with D2d.

Again using Nvidia 7050 D3D9 hardware.

Certainly seems relate to the 'tab showing through' issue. It looks to me like it's something from the chrome window when the content window hasn't been drawn yet. The size of the rectangle is somewhat odd though. I suspect what caused this is we're doing numerous memory usage optimizations which might slightly increase time for switching tabs, that shouldn't make such a big timing difference though.

I think your right, that there is a general painting grey before Content change bug, maybe Roc you can take a look at. See also bug 574638 - grey UI on startup and some comments I make about resize borders produce similar results, and Jim, I haven't filed a bug on that yet.

Ok, I see now whats happening here. Its painting the Normal window first when switching tabs just like bug 574638 does on startup, and then its painting the maximized window, like a resize, hence the grey area is the difference between the two. This is a running variation of bug 574638.

I tested this by having a normal mode window half the screen height as the maximized mode window.

So then if I resize the Normal Window to the size of of Maximized, but not Maximized state, it doesn't stop remembering this grey size. If I restart firefox then it stops, it becomes white, with the same exact observations I made in bug 574638 about it not showing grey unless different dimensions exist. I then see transparency, but not sure how closely tied this also would be to bug 532106.

(In reply to comment #5) > See also bug 574638 - grey UI on startup and some comments I make about resize > borders produce similar results, and Jim, I haven't filed a bug on that yet. I'm thinking this is the same as bug 595614. This bug might just be a dupe of bug 574638 then, but I should double check I don't see this still.

Related items are resolved-fixed, need to determine if this bug can be closed. If errors are still seen, report current OS and Firefox version. Version 45.0 Build ID 20160303134406 User Agent Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Firefox/45.0 *Aero unavailable

Closing this as works for me, due to inactivity and lack of response to contradict comment 10. Feel free to reopen the bug and provide a test case if the issue still reproduces on a current build.