1472537 - Miscolored theme portion when using multiple resolutions

Status: RESOLVED DUPLICATE of bug 1470341

(Firefox :: Theme, defect)

Description

[Estecka]

Attachment: Two themes with a miscolored portion

This started happening to me yesterday, after I updated to firefox 61.0
(Updates are set to manual)

This naturally happens when using at least two monitors of different resolutions, but is still reproduceable using a single monitor.

• Bug description : 
Sometimes, a portion of the theme will appear miscolored, in the top-left corner of the window.
The miscolored portion's size vary depending on where the window was created: it starts showing when the window becomes wider than the screen it was created on.

• Tested themes : 
https://addons.mozilla.org/fr/firefox/addon/black-rock-shooter-cyrado/
https://addons.mozilla.org/fr/firefox/addon/really-cute-bird
(Presumably, many more should be affected.)

• Reproduction steps : 
1- Install one of the themes above.
2- Create a new tab. (There needs to be at least two tabs open.)
3- Drag a tab out of the window, into the smallest screen. This creates a new window there.
4- Drag the new window into a bigger screen and maximise it.
RESULT => The new window now shows a miscolored portion  when maximised on this screen. 

This is the typical scenario when using firefox normally, a fastest way to check for the bug is to simply extend any window as far as possible across multiple screens at once. On a single screen, this is achievable by dragging the window through the right border before extending it further.