@Laszlo Nagy sorry, long weekend here. I've mocked up a dummy file to illustrate.
Setup Surfaces - Black Frame
Setup Surfaces - Silver Frame
Setup Surfaces - Obscure Glass
Setup Surfaces - Blue Glass
Setup Graphic Override - Override Foreground (Vectorial Fill)
Override foreground (Vectorial Fill)
Setup Graphic Override - Override Background (Surface Colour)
Override Background (Material Fill)
Result - No Overrides
Result - Override Foreground (Vectorial Fill)
Result - Override Background (Surface Colour)
Hope that Illustrates it clearly.
Was having real trouble getting the schedule to reliably update with graphic override settings, CMD+OPT+SHIFT+R (force rebuild) wasn't rebuilding them, ended up having to close all tabs, sit on the floor plan with the correct view settings and open the project map of the schedule and THEN force rebuild. Which seems a bit excessive.
AC 24 5004 AUS
iMac OSX (10.13.6) 4.2ghz i7
8gb ram/8gb vram