When working on legacy .cs files, the scrollbar is often a rainbow of Code Analysis marks - so the default, low opacity grey scrollbar thumb is virtually invisible.
So I changed this setting:
JetBrains Rider 2019.3.1 → File → Settings → Editor → Color Scheme → Vertical Scrollbar → Thumb → Background → FF00FF
However even after restart of Rider it doesn't change.
Not sure if it's relevant, but the above settings dialog doesn't allow the Foreground colour to change
What am I missing?