Don't explicitly send MotionNotify event during Resize (GeometryWindow)

Don't explicitly send MotionNotify event during Resize (GeometryWindow)

When calling DisplaySize() from a resize event performed on a window,
ensure we use the window's last event (which will be MotionNotify
anyway) otherwise this completely confuses the GeometryWindow as it has
to then update itself each time.

When using Xinerama/TwinView, the effect is that the GeometryWindow
flickers and/or displays itself on the opposite screen to where the
pointer is, because the x/y positions don't take into account the
location of the pointer from the original hand-crafted event, but are
correct from the execute context the window being resized is called in.