STR: (Nightly 42.0a1 (2015-08-06)) 1. Make sure you have hidden menu bar, bookmarks bar and title bar 2. Switch to Fullscreen mode 3. Press Alt several times RESULT: [watch video] Part of toolbar (some pixels in height) is visible on the top of the screen EXPECTATIONS: one of 2 will happen: A) Nothing B) I will see all toolbars in their current states (as of non-fullscreen mode), including menu bar, that will be visible. When I press Alt again in this scenario, I expect all toolbars to hide again.

I figured out that it doesn't occur on Release(39), but presented on DevEdition(41) and Nightly(42). Also, the problem is a bit more serious. STR_2: 1. Right-click Australis menu button -> check "Menu bar" 2. Press F11 to enter Fullscreen mode RESULT: see attachment. It makes using tabs much more complicated.

Pay attention that now bug 1192655 is fixed, so only STR in comment 1 works. But this bug is still valid

Pushlog: > https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=3fca18104696e85d3f90c84802e03479b9c023ee&tochange=4b47c3f074a36bb16295bf3127268094a64ed7db I think it's bug 1176233.

This is because the gap was added via the rule: > #toolbar-menubar:not([moz-collapsed="true"]):not([autohide="true"]) ~ #TabsToolbar { > margin-top: 3px; > } And since bug 1176233, we no longer use moz-collapsed for collapsing toolbars.

Review commit: https://reviewboard.mozilla.org/r/54506/diff/#index_header See other reviews: https://reviewboard.mozilla.org/r/54506/

Review commit: https://reviewboard.mozilla.org/r/54508/diff/#index_header See other reviews: https://reviewboard.mozilla.org/r/54508/

Comment on attachment 8755276 [details] MozReview Request: Bug 1191966 part 1 - Remove rules for unused moz-collapsed attribute. r?dao We need to keep moz-collapsed support in minimal-xul.css, it's used by add-ons.

Comment on attachment 8755277 [details] MozReview Request: Bug 1191966 part 2 - Avoid adding margin-top on tabs toolbar when in fullscreen mode. r?dao Please use #TabsToolbar:not([inFullscreen])

Comment on attachment 8755276 [details] MozReview Request: Bug 1191966 part 1 - Remove rules for unused moz-collapsed attribute. r?dao Review request updated; see interdiff: https://reviewboard.mozilla.org/r/54506/diff/1-2/

Comment on attachment 8755277 [details] MozReview Request: Bug 1191966 part 2 - Avoid adding margin-top on tabs toolbar when in fullscreen mode. r?dao Review request updated; see interdiff: https://reviewboard.mozilla.org/r/54508/diff/1-2/

https://hg.mozilla.org/integration/fx-team/rev/af0b7a2ad92a https://hg.mozilla.org/integration/fx-team/rev/ef5addc3db7d

This seems to have been landed on mozilla-central a while ago. Not sure why the bug is not updated. https://hg.mozilla.org/mozilla-central/rev/af0b7a2ad92a https://hg.mozilla.org/mozilla-central/rev/ef5addc3db7d

https://hg.mozilla.org/mozilla-central/rev/af0b7a2ad92a https://hg.mozilla.org/mozilla-central/rev/ef5addc3db7d

I have reproduced this bug with Nightly 42.0a1 (2015-08-06) on Windows 7 , 64 Bit! This bug's fix is verified on latest Developer Edition (Aurora) which is 49.0a2 (2016-07-08). Build ID 20160708004052 User Agent Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:49.0) Gecko/20100101 Firefox/49.0

Thanks Maruf Rahman for the tests. I was also not able to reproduce this issue on Firefox 49.0a2 (2016-07-10) and on Windows 7 x86. I am marking this issue Verified Fixed.

Too late to bring to beta, but this will be fixed in 49 release.