SUMMARY
In System Settings when I click on the "Get New (whatever)" button at the bottom of the KCM box, a new window pops up with a title bar.  On the title bar are minimize, maximize and close buttons.  The minimize and maximize buttons work as expected.  But, if I click on the close button, nothing happens.  If I double click on the close button, it functions as a maximize button, maximizing the widow (if not full screen) or returning to "normal" size if full screen.  The close button is also the wrong appearance for my color scheme, the close button is grey when it should be orange.  Perhaps it is "greyed out" to show it is non-functional?

I would think if it supposed to be non-functional the button should be removed. 



STEPS TO REPRODUCE
1. Open system settings.  
2. Go to a KCM where you can download additional options, for example Global Theme or Icons.
3. Click on "Get New ..." button."
4. Click on close button on the title bar.

OBSERVED RESULT
Nothing happens with single click.
Double click on the close button functions the same as maximize button.

EXPECTED RESULT
Window should close.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
Operating System: KDE neon 5.23
KDE Plasma Version: 5.23.4
KDE Frameworks Version: 5.88.0
Qt Version: 5.15.3
Kernel Version: 5.11.0-41-generic (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-3740QM CPU @ 2.70GHz
Memory: 23.0 GiB of RAM
Graphics Processor: Mesa DRI Intel® HD Graphics 4000
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION