This is a memory problem with the Mac. Allocating it more RAM will reduce the freeze effect, but unfortunately, doesn't eliminate it. I am not 100% sure, but I think you OPTION+CLICK the app file and go the properties box. Maybe it's get info. Look for some place where you can tell it how much RAM to use. I am not sure of the exact procedure because I don't have a Mac on hand to try this. It has reduced problems for others in the past, but none have reported a complete fix.

Does this work for you?