Hi there,
I'll be honest with you - I don't think this is a good "hack". The reason is simply that a change of the colour doesn't change the type/characteristics of the widget used (the drawer in this case). It still behaves like a drawer, is a drawer and is attached to the window and not in-set - it has advantages/disadvantages. Your change doesn't actually improve usability (from my POV). I'm sorry if I sound too harsh - it's not my intent.
Regards,
Milen