How to move a file after some time it has been opened?

Greetings,
I've set up a rule that look for .dmg files into a folder, and, if it has been opened, after some time Hazel move it to the trash.
Alas the rule trashes the file as soon as I download it.
How do I solve it?
I've tried by using last opened "is before" and "is not in the last", but I wasn't able to solve.
Thank you!
I've set up a rule that look for .dmg files into a folder, and, if it has been opened, after some time Hazel move it to the trash.
Alas the rule trashes the file as soon as I download it.
How do I solve it?
I've tried by using last opened "is before" and "is not in the last", but I wasn't able to solve.
Thank you!