Create a 2D window and then manually focus a different window on your desktop, call SDL_PumpEvents() so the X11 driver sets its this->hidden->switch_waiting, then set a fullscreen OpenGL window (which makes the X11 driver tear down and create a new window instead of just resizing the existing one), poll for events, and the newly-created window will think it needs to pop back to a window. Fixed by resetting switch_waiting to zero if X11_CreateWindow() had to tear down a previous window.

noinst_HEADERS =	\
	extutil.h	\
	panoramiXext.h	\
	panoramiXproto.h \
	xf86dga1.h	\
	xf86dga1str.h	\
	xf86dga.h	\
	xf86dgastr.h	\
	xf86vmode.h	\
	xf86vmstr.h	\
	Xinerama.h	\
	Xv.h		\
	Xvlib.h		\
	Xvproto.h