Opening side panel messes with display setting

Quite unexpected:
I keep side panel close at most of the times, but when I open it it changes my background colour from ‘custom’ to ‘application’.

Hi Piotr - just on opening? Does the Display panel need to be on top for this to happen?

-Pascal

I tried to reproduce the problem on a new session and I couldn’t, which means it was a temporary weakness only. Should it happen again, I will let you know.
P