It all works fine on Windows - the mouse cursor simply goes into the minimally-resized window and redrawing stops. With OSX though, the window resizes to the cursor and out to it's minimum size again - hence the flicker.
Any ideas or solutions would be very welcome.
While I'm here ...

I once found a method on this forum to set the mouse position but I can't seem to find it now.
Again, if someone could be so kind ...
Dave