Can anyone else confirm that they got inactive borders coloured under D3D?
What did you do exactly? Do you have any custom theme installed? I have not found any usable way to identify each window (including its current state), so inactive windows are identified by its colour which seems to be hardcoded to RGB 235,235,235. This colour is replaced with that one which you specify in HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\DWM:ColorizationColorInactive as e.g. 0xffff0000 (for red colour) It should work even in Direct2D mode. However remember, that in Direct3D mode, this colour is modified by ColorizationColorBalanceInactive settings.