Does this sound familiar to you?... so, we have an idea, put some squares on the screen and do a bit of coding to see if it works. The trouble is most of the code is global to the whole game. No problem... cut and paste the code to the 'Global Events'. Right, run the program... oh dear, it comes up with an error message 'This program has performed an ilegal operation and has shut down.'. Sometimes it will allow you to carry on messing with the code but there are occasions when it exits from MMF completely... frustrating or what!