FreeDisplay()returns, the specified display will be no longer available.
Please note that you cannot call this on the current display. You must
select an other display using SelectDisplay() first before you can call
FreeDisplay(). This is because Hollywood always requires a current
display. Freeing the current display would lead to a non-existent current
display and this is not supported by Hollywood. There always must be a
display that is the current one. Even if all displays are closed and there
is no visible display at all, Hollywood will internally still have a
current display that can handle calls that draw graphics.