[BUG] Theme color selector is broken

[SniverDaBest]

Describe the bug
When trying to edit the color of something in a theme, the background of the popup is completely transparent, and you're unable to select a color, as it reverts back to #ffffff.

To Reproduce
Go to Settings -> Themes -> New Theme (or edit an existing one) -> Click on a color selector box
The box background is transparent, and no color works.

Expected behavior
I believe that I should be able to set some custom colors for Moosync.

Screenshots

• OS: Windows 10
• Version 10.3.2

Additional context
Add any other context about the problem here.

[SniverDaBest]

This also happens on Fedora Workstation 40/41.