Steps to reproduce: 1. Set browser.tabs.drawInTitlebar;true 2. Open any web page 3. Go to full screen What happens: The tab bar becomes semitransparent and allows desktop background to be seen. Expected result: Tab bar colors should look like it does when not in full screen. Screenshot attached. 11:57.15 INFO: Narrowed inbound regression window from [59d4d986, 9f3cde2c] (3 builds) to [59d4d986, 9bde1b9b] (2 builds) (~1 steps left) 11:57.15 INFO: No more inbound revisions, bisection finished. 11:57.15 INFO: Last good revision: 59d4d98688e4cfd32a267f97720bc7fe07305b07 11:57.15 INFO: First bad revision: 9bde1b9b0810e1c3eb170fbace15eb6aa250b637 11:57.15 INFO: Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=59d4d98688e4cfd32a267f97720bc7fe07305b07&tochange=9bde1b9b0810e1c3eb170fbace15eb6aa250b637

Martin, could you investigate this?

Jared, this looks like a variant of Bug 1447775, should be fixed by Bug 1356920. We can apply a workaround if Bug 1356920 does not land in time.

(In reply to Martin Stránský [:stransky] from comment #2) > Jared, this looks like a variant of Bug 1447775, I don't think this is true, or at least I don't see how these two are related...

(In reply to Dão Gottwald [::dao] from comment #3) > (In reply to Martin Stránský [:stransky] from comment #2) > > Jared, this looks like a variant of Bug 1447775, > > I don't think this is true, or at least I don't see how these two are > related... Sure, let's investigate that. Asif, which system / desktop environment and Gtk+ theme do you run?

GNOME 3.30.1 on Ubuntu Cosmic Using the default Adwaita theme; the issue doesn't appear in "Yaru".

I think I can see that. Let's wait until Bug 1356920 lands.

Pushed by aciure@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/d5edb89adaa1 Set transparent titlebar background for normal sizemode only, r=dao

Does this need a Beta approval request?

Yes please.

Comment on attachment 9023080 [details] Bug 1501161 - Set transparent titlebar background for normal sizemode only, r=dao [Beta/Release Uplift Approval Request] Feature/Bug causing the regression: Bug 1493145 User impact if declined: Users can see transparent titlebar when running on Gnome, have disabled system titlebar and browser goes fullscreen. Is this code covered by automated tests?: No Has the fix been verified in Nightly?: Yes Needs manual test from QE?: No If yes, steps to reproduce: List of other uplifts needed: None Risk to taking this patch: Low Why is the change risky/not risky? (and alternatives if risky): Minor style change for Linux/gnome/full-screen mode. String changes made/needed: none

Comment on attachment 9023080 [details] Bug 1501161 - Set transparent titlebar background for normal sizemode only, r=dao linux css regression fix, approved for 64.0b11

[testday-20181221] User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:65.0) Gecko/20100101 Firefox/65.0 OS: Windows 7 (64bit) Status: Fixed & Verified Steps to Reproduce: 1) Start the Firefox 65.0b6 Browser (64-bit) 2) In new tab, type about:config 3) In the search option type, search for browser.tabs.drawInTitlebar 4) Make the value of browser.tabs.drawInTitlebar - > true 5) Click on View - > Fullscreen or Press F11 key I Dont find any changes in tab. The tab was looking normal like ever. I have Reproduced the bug & The bug has been fixed.