1) Launch "Font Management" from application menu 2) Press Ctrl+Q to close the font management window Expected: Font Management window closes Actual: Font Management window remains open. NOTE: if the font management view is opened by starting "System Settings" and then selecting "Fonts", the window can be closed with the keyboard shortcut. This bug only surfaces if the font management tool is opened 'standalone' from the application launcher.
Confirmed on Arch Linux, plasma 5.12.3.
This issue appears to be a kcmshell5 issue across all modules. *** This bug has been marked as a duplicate of bug 397362 ***