Windowed mode (Windows)
When switching from full screen to windowed mode, it doesn't actually let you go into windowed mode. You can only switch to Full Screen Windowed or Full Screen, hitting windowed and then apply does nothing.
Tosado posted this bug on04/19/17
On further inspection, I've found that windowed mode does work, but it only support 640x480 and 800x600, it no longer supports any of the higher resolutions.