Dev App 1.3.9 (433)

[Celti]

- Restored exclusive fullscreen mode as windowed fullscreen caused performance problems on many setups.  If you still want windowed fullscreen, you can use the "-popupwindow" launch option.

This is not working for me for some reason. It just stays in exclusive fullscreen mode and if I switch to windowed mode in-game it doesn't let me tab out, it just keeps showing the game. 

[Watchmaker]

"-popupwindow" only affects Windowed mode.  Fullscreen mode is exclusive fullscreen no matter what.

There appears to be another Unity bug of some kind at work, as well: if you switch from fullscreen to windowed mode, the game window remains on top.  You can work around this by simply quitting and relaunching the game; if it starts in windowed mode, there's no problem.