[X11] Menu regression in 11.0.8 and 11.0.9

[timschneeb]

Describe the bug

Two issues with menus on X11 popped up since Avalonia 11.0.8 (also present in 11.0.9):

• Borders and rounded corners of menus are transparent and show the background behind the root window
• Menus are cut off and only drawn within the root window's bounds

To Reproduce

Steps to reproduce the behavior:

1. Build the 'ControlCatalog.NetCore' sample project
2. Go to 'Menu' and open a menu

Expected behavior

• The borders/corners of the menu should not show the background behind the root window
• Menus should not get cut off at the border of the root window

Screenshots

ControlCatalog:

In my app, it's much more noticeable due to the rounded corners:

Environment

• OS: Arch Linux X11
• Avalonia-Version: 11.0.9

Additional context

• Avalonia 11.0.7 worked fine
• Possible cause: Use popupParent as X11 parent window #14366

[curvedspace]

I see a similar effect on tooltips with Linux.

[dc740]

wayland is also affected:
sn4k3/UVtools#836 (comment)

UVtools had to downgrade to 11.0.7 to get it to work again.

[kekekeks]

Need to release 11.0.10 with that revered PR.

[timschneeb]

Fixed by https://github.com/AvaloniaUI/Avalonia/releases/tag/11.0.10