@neauoire in every Mac OS 6 (or before?) to current, if you hold command (Apple) and drag a window which is *backgrounded*, the window will move without being foregrounded.
Other hidden operations which are related but not relevant to Notepad: Holding option and clicking close closes all windows in the current application; holding cmd and clicking the title bar title shows the path the file is at (if the window represent a file).
@mcc I'm not planning on implementing operating system and windowing behaviours, I'll end at the Note Pad application I think ^^;