User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0 Build ID: 20150807085045 Steps to reproduce: * Update Firefox to Version 40. * Open in Safe Mode Actual results: A dark gray bar under the tabs appears, which doesn't match the title bar. Expected results: Colors should be consistent.

Additionally, the window controls (minimize, maximize, and close) aren't vertically centered, as shown in the attached screenshot.

Could you test with HWA disabled, please. https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles (restart FF to apply) In addition, type about:support in the location bar and copy here the section "graphics". Are you using a special theme in Win 10? If yes, does it work with the default standard Win 10 theme?

Sorry, it's https://support.mozilla.org/en-US/kb/forum-response-disable-hardware-acceleration for disabling HWA.

I am using default Win 10. I have disabled HWA and there appears to be no change. Here is what graphics shows: Adapter Description NVIDIA GeForce GT 720 Adapter Drivers nvd3dumx,nvwgf2umx,nvwgf2umx,nvwgf2umx nvd3dum,nvwgf2um,nvwgf2um,nvwgf2um Adapter RAM 1024 Asynchronous Pan/Zoom none Device ID 0x1286 Direct2D Enabled Blocked for your graphics driver version. DirectWrite Enabled false (10.0.10240.16390) Driver Date 7-22-2015 Driver Version 10.18.13.5362 GPU #2 Active false GPU Accelerated Windows 0/1 Basic (OMTC) Subsys ID 108710de Supports Hardware H264 Decoding false Vendor ID 0x10de windowLayerManagerRemote true AzureCanvasBackend skia AzureContentBackend cairo AzureFallbackCanvasBackend cairo AzureSkiaAccelerated 0

I have a similar problem. I get the same gray bar, but it extends to the titlebar as well. I dunno if that's what it's supposed to look like now, but it should seriously stay consistent with the OS theme(white).

This is caused by enabling the title bar, which makes out darker-grey tab strip background look strange, because it no longer extends to the top of the window. Philipp, what do you want to do here? My suggestions, in preference: 1) Remove this option. It's out of place on Windows 10 new UI. 2) Change the titlebar background to a matching grey (not sure if we can do this?) 3) Change the tabstrip background to match the titlebar when it is enabled.

Oh, and calling this a P2 because it's pretty visually gross for an option that we added back in Australis because significant numbers of people wanted a titlebar back (pre-Win10, natch).

(In reply to Justin Dolske [:Dolske] from comment #6) > This is caused by enabling the title bar, which makes out darker-grey tab > strip background look strange, because it no longer extends to the top of > the window. > > Philipp, what do you want to do here? My suggestions, in preference: > > 1) Remove this option. It's out of place on Windows 10 new UI. > > 2) Change the titlebar background to a matching grey (not sure if we can do > this?) > > 3) Change the tabstrip background to match the titlebar when it is enabled. I agree with your assessment and would also prefer to remove the option on Windows 10 (if not in general, but we can start here). Do we have any idea on how widely it is used? I found this https://useradvocacy.mozilla.org/dashboards/telemetry-ui/?date=2014-12-30&channel=release (look at the very bottom), but that seems... wrong. But even without data, I'd be happy to remove the option in Nightly and see what happens.

One thing that needs to be considered is that on Windows, a common usage is to click and grab on the title bar to resize and move. Without the separate title bar, this functionality gets much much harder.

After bug 1196266 landed, this is no longer a problem for focused Firefox windows. However, this is still a problem for unfocused windows, and in fact it feels worse now because the transition from focused to unfocused gives goes from one solid block of color to two blocks of color. See attachment 8884395 [details].