It's complicated, but the simple explanation is when stuff is placed on the clipboard, it can be done two ways1. Placed completely on the clipboard
2. The program where you cut/copy from can tell the clipboard it has data ready, and that it will provide it later
When data is retrieved from the clipboard (paste) it can be done two ways
3. Get all the date from the clipboard and paste it in
4. Hook into the clipboard viewer "chain", and see changes to the clipboard as they happen.
In version 4.22, programs which do 2 or 4 with graphics (some paint programs for example) can trick Activ E-Book Compiler into thinking the user is trying to do PrintScreen, and there's no way for the ebook to tell the user hasn't.
The answer in 4.22 is to not run one of these programs at same time as the ebook is open. (Shouldn't happen for most users anyway).
As far as I know (it's obviously not possible for us to test with every possible paint program), the problem will be solved completely in the forthcoming version 5.
