Atm in Windows 7 (maybe some other OS's use this too), if you drag and drop Spotify title bar on top of screen, it doesn't maximize the window like other windows and applications do. Same with drag and drop into side of the screen, moving the title bar whilst the window is maximized nor windows+right/left/down arrow keys (or any other window layout manipulation hotkeys (for multiple screens)).
Please fix this, it's pain in the ass when trying to do it fast in the middle of the raid event in WoW, or any other multiplayer gaming event when you have 3 sec time to do: activate Spotify, doubleclick title, drag it to secondary screen, doubleclick title, and click "play" and back to game, when you could do all that with: activate Spotify, drag and drop to top of secondary screen, click "play" and back to game.
Saves seconds and nerves of nerds, and you wouldn't lose users for such tiny mistakes.
PS. Also add that output selection option, it's not hard to implement and even Billy, the lightest mp3 player out there, has that option. Y U NO HAVE THT??