Maximized(not fullscreen) firefox top edge bleeding into another monitor above.
I've completely identified the problem(maybe). But I don't think any community help can fix this. Probably needs mozilla's attention for this. I just don't know how to get that attention.
Windows 10. This happends when display is on a 'OverUnder' setup, making window maximized(not F11 fullscreen mode.) in bottom display introduces white(usually) stripe bleeding into top display.
Some properties of this bug.
- Taskbar hides this stripe. So most bottom-taskbar people can't see this.
- It sometimes grabs normal firefox titlebar so It's colored and sometimes you can see tabs.
- Enabling windows default titlebar fixes this problem because (obviously)default windows behavior is not broken. But it's ugly&unnecessarily uses space.
This bug is combination of Windows 10 maximize animation and poor handing of that animation by firefox. When you grab any window and maximize it. You can see that window doesn't just instantly becomes maximized, rather they start from just little bit smaller than maximized. When Firefox is playing this animiation, for some reason, only top edge introduces white stripe; And that white stripe just moves over to other monitor. You should be able to see this animation even if you don't have second monitor. Have to be focused because it's fast.