Not sure whether I'm going stupid or that maybe I have a older copy of the program , have had for couple of years but I assumed that it would update. I will add that I have the free copy as want to see if it will do what I want before purchasing, and that Im running on a emulator from a mac, which can slow thing down a bit , but not enough to miss check boxes
have enclosed a screen vidio of what I do to bring up a mask ,and can see nowhere to uncheck a box
(or would have done if I could see where to save att. On clicking insert other media ,it tells me I dont have any existing , or asks for a http)