Does not detect all fullscreen modes

[tempelmann]

This is more a FYI for those (like me) who seek a complete solution and stumble on this.

It appears it only detect the mode where an app's window goes into fullscreen mode, but not when the entire app uses different ways.

For example the way VLC uses fullscreen mode is not detected by this code, unfortunately. I am still seeking a clean solution to detect those - if anyone knows, please comment.