It would be nicer (from the point of view of updating the window) to do the drawing off-screen. That way an update could be done by transferring the pixel pattern (?). As it is an update can only be done by recalculation of the window, which is a bit time consuming. Does anyone know how to work QDOffscreen? I have read the chapter in IM but can't work how to apply it. Thoughts would be appreciated. Meanwhile have fun with the bugs. Drink only boiled water. Alan Fry Attachment converted: mouse1:Z^3.sit (SITD/SIT!) (00004A28)