Fix windows getting scrambled after hotplugging an output

Currently, if an output is hotplugged, all windows will be scrambled, which is highly annoying.

With this change, windows will stick to their outputs if an output has been connected or disconnected.

BUG: 296673 BUG: 378896 BUG: 412703 BUG: 443698 (there are potentially much more similar bug reports)