Changed how the focus is reverted.
Changed how the focus is reverted.

When the input focus is set to None, it causes grabbed keys to be
ignored, preventing certain window manager actions. Now, if the input
focus is set to None, XData instead sets the focus to the root window so
that those grabbed keys can be used again.

8l/SmallWM,8l/swm,8l/SmallWM,8l/swm