>>> My Info: Win7_64, Nightly 47, 32bit, ID 20160218030349 STR (A): 1. Open firefox. Make sure that there's only 1 firefox window opened. Switch it to normal mode. 2. Press F11 to switch to fullscreen mode 3. Click "Close" button at the top right of the window 4. Open firefox. Make sure that there's only 1 firefox window opened 5. Click "Resize" button at the top right of the window STR (B): 1. Open firefox. Make sure that there's only 1 firefox window opened. 2. Open new window, switch it to normal mode. 3. Press F11 to switch to fullscreen mode 4. Click "Close" button at the top right of the window 5. Press Ctrl+Shift+N to restore the window closed in Step 4. 6. Click "Resize" button at the top right of the window AR: Window switched to normal mode, but its dimentions (height/width) are equal to maximized window ER: Window should switch to normal mode preserving dimentions. This is regression between 2014-05-20 and 2014-05-21 (regressionwindow-wanted) > https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=cb9f34f73ebe&tochange=9d8d16695f6a Release 31 is unaffected. The reason I'm filing this only now is that when I started to report bugs, there already were some filed fullscreen bugs && I didn't know _what_ is considered a bug.

I believe you need to maximize the window before entering fullscreen mode to reproduce this bug. Given we are able to restore to the original size when we close Firefox with window maximized, I think this bug is fixable.

This is a bug we want to fix, but I don't have plan working on this currently.

(In reply to Xidorn Quan [:xidorn] (UTC+8) from comment #1) > I believe you need to maximize the window before entering fullscreen mode to reproduce this bug No. As said in comment 0, I switch directly to Fullscreen from Normal mode. If I switch from Normal mode to Maximized, then to Fullscreen and close browser, - everything works as expected. Request screencast if it's necessary. If you're testing Win10 and see something different - that's probably Win10-specific.

I tried Firefox 44 on my Windows 7 VM, and I cannot reproduce this issue with your STR either. Its behavior seems identical to what I see on Windows 10.

I have tested 3 PC with Win7 _installed_ (NOT VM): 2 different home PCs and one of machines in my university. All of them show the bug after STR(A) and STR(B) and do NOT show the bug if in scenario (A) I add Step 1.5 "Switch window to maximized mode" and if in scenario (B) I add Step 2.5 "Switch window to maximized mode". All of PCs have russian version of Windows7 installed. Also, there were some issues in the past which weren't reproducible on win7 VM on Mac (bug 1189438). VM is the worst way to reproduce an issue. I think there should be a special team confirming all such issues (e.g. bug 770773)

Well, the problem is, if I cannot reproduce the issue myself, I don't have idea what is happening, even a special team can reproduce it. VM generally has identical behavior as a real machine in this field. From your description, I'd actually suspect it could more likely be related to the locale rather than whether it is in a VM. But I don't really have idea how this could happen...

Hi Arni, I can reproduce this issue only with provided STR(B) on latest Firefox (44.0.2) release and latest Nightly (47.0a1) build. I have also performed a regression, and I have obtained the same pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=cb9f34f73ebe&tochange=9d8d16695f6a. Firefox: 47.0a1, Build ID: 20160225030209 User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0 Firefox: 44.0.2Build ID: 20160210153822 User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:44.0) Gecko/20100101 Firefox/44.0 Considering this I will remove the "regressionwindow-wanted" keyword. Thanks, Cosmin.

OK I realize how to reproduce this issue. I guess this is an issue of session restore, since the window size is restored not from XULStore but from something else.

This bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1005619 Looks like a good candidate for causing this.