Adding resources to private activities works, although an error message appears when adding applications because kactivitymanager tries to move the .desktop of the app to private folder. kactivitymanager succeeds in copying the .desktop but it cannot delete the original file and the error message "permission denied" appears. I think we should suppress that error message or use copy instead of moving when we known we cannot delete the original file.

Another problem is that sometimes the resources containters (Apps, Bookmarks, Documents) in private activities disappear after rebooting the device. That do not happen with public activities. Some resources that can be added only once (Boomarks, Documents) are not listed anymore in "Add Items".