Created attachment 121294 [details]
A simple black background with two red dots

SUMMARY


STEPS TO REPRODUCE
1. Open Krita and use the brackets keys to change size of brush 

OBSERVED RESULT
Brush size changes, but I cannot tell what size the brush is based on the slider at the top of the window.


EXPECTED RESULT
Brush area size changes [i.e. 10 pixels to 12 pixels, and the slider filling up with color, etc.]


SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
I can physically use the cursor to operate the slider, though this is not precise enough to warrant nondisruptice use.