Hello,
In the Agent Config settings you can chose which protocols to control, including FTP.
Concerning screen capture, DLP (since 14v) can block the PrintScreen button. Also configured through Agent Config. If activated, you can assign a response rule to the FTP protocol to block the action of certain Policy.
I am not aware of a possibility to block/allow temporarily a Policy (or Response Rule) natively. Unless you use some script.
Regards,