http://bugs.winehq.org/show_bug.cgi?id=58661
--- Comment #4 from Stian Low wineryyyyy@gmail.com --- (In reply to Stian Low from comment #3)
Could not reproduce window cloning bug but the black squares appear where menus are supposed to be rendered.
Partially reproduced the window cloning using GE-Proton-10-15.
The menus also turn from black boxes to their normal rendering when hovering the mouse over the items.
The window cloning may be related to emulate virtual desktop like features which GE-Proton-10-15 seems to run by default.
The cloned window contained no title bar and was unresponsive. The original window remained functional but was always behind the cloned window so z order broke.
Using winecfg -> Graphics -> Emulate a virtual desktop for vanilla wine 10.13 produced similar behavior but the discord button now crashes immediately upon open rather than on close. The menus also behaved similarly by changing from black to rendering correctly as the mouse is hovered over the items.
Same behavior all the way back to GE-Proton-9-5 (wine-9.5).