I'm running ninja forms in WP 3.5 in a test situation and I can create new forms change the settings etc. then I go to 'field settings' but when I click on the fields nothing happens. I can hit save field settings and it says it was successful but I am not able to add any fields to my forms.
I updated the plugin from 1.x version to 2.0.1 but I did not have any forms yet. After upgrading all my plugins yesterday I also updated WordPress to 3.5 and I deactivated all other plugins but no change.