Created attachment 8669488 [details] screenshot - Overflow tooltip in toolbar breaks if I switch from narrow to maximized window using Win+Up.png STR: (Win7_64, Nightly 44, 32bit, ID 20151003030225, new profile, safe mode) 1. Make sure there's no overflow in toolbar when browser window is in maximized mode 2. Dock browser window to the left side of screen (Win+Left), reduce the window's width to trigger overflow in toolbar 3. Click overflow button >> 4. Press Win+Up to maximize the window 5. Press Win+Left to trigger overflow again 6. Click on the overflow button several times Result: After Step 5, you see empty overflow tooltip. After Step 6 it still contains no items Expectations: Overflow tooltip should always contain buttons which are not visible in narrow toolbar Note: I noticed one thing - if I switch from docked window with overflow to normal (not maximized and not docked) window with overflow, tooltip doesn't disappear.
Actually, with different window sizes, it's reproducible for Win+Left/Right/Up/Down and F11. The only important thing is that in Step 3 the toolbar doesn't have enough width to display all items, and after Step 4 it does. Switching from narrow window to large - breaks the overflow popup
Actually F11 behavior was fine before bug Bug 1160014. This bug may be converted into F11-only issue, and other cases may be handled in separate bug, since F11 is the only regression here. > pushlog_url: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=07bcf36f5ab25e4cc58f33e9732246c252762dcd&tochange=ee99ebac7761ad95d201990755bba2f013cad866
I suspect that this "regression" is because of part 3 of bug 1160014 which backed out bug 634586, so that the window doesn't hide then show again for fullscreen transition. But I don't think it's worth backing out that part and regress several other bugs for this specific case. This issue should be fixed as a whole.