If one sets e.g. the Rhino.UI.ThemeSettings.Frame.Background value to a custom color using the Rhino Options > Advanced menu, then goes to the Rhino Options > Appearance > Colors menu and simply presses Cancel, the Rhino.UI.ThemeSettings.Frame.Background value is reset to the default value:
As you can probably tell from the title of the bug report, I would call that the expected behavior but I see that this behaves as you expect in all other cases… Oh well…
→ RH-77221 Options: Cancel to close dialog reverts changes
-wim
Yes, the second (30 second) video demonstrates the issue (I open Rhino 8 where I have already set GUI colors via the advanced menu prior, then navigate to Appearance > Colors, click Cancel, which resets the GUI colors).