When I (as admin user) am also the teacher in a course, and click on the add a resource or activity, the pop up box is greyed out and I cannot do anything but back out of it. In a course where I am not also the teacher, it appears just fine and if I log in as a teacher who is not also the admin user, it also works just fine.
Moodle 2.6.1+ (Build: 20140123)
Any suggestions? Can anyone else reproduce?