Dark mode is not working correctly

[MrAndre96]

Bug description

When I use dark mode (QDarkStyleSheet) a lot of buttons are unresponsive and the layout is incorrect. Also the tags are black which is not really readable on a dark theme

Steps to reproduce

1. Go To the interface settings and change the theme
2. Just try some things like opening a new tab or the Plus button etc
3. You will see that you need a lot of presses for it te respond which would not happen in the light theme

Expected behavior

That the dark theme would work as well as the light theme

Screenshots

Video to explain the issue

System information

• OS: Windows 10
• Grabber version: Latest nightly version

[Bionus]

Seems to be caused by QTBUG-86587
Only happens in Qt 5.15.1 which is the version currently used by Grabber. Fixed by https://codereview.qt-project.org/c/qt/qtbase/+/313706. Will need to bump to 5.15.2.