On MacOS Catalina, Pinta does not open the protected folders like Desktop. When I try to open Desktop in pinta's file open dialog, I get the system error message "operation not permitted". When I give "full disk acces" to Pinta the MacOS Security Settings, this does not help. There is no way to grant permissions to Pinta in "files and folders" as it is not listed there, and the plus icon to add apps is greyed out on my mac.

Instead of the system error, Pinta should request access to the folder, so I can grant access.

This seems to be the same problem which GIMP did have with MacOS Catalina, they solved it in the lasted upgrade.