CiviEvent: Unable to de-select a selected profile

It seems that CiviCRM installs which have been upgraded to 2.2.7 can have had duplicate entries created in civicrm_uf_join assigning more than two profiles to a single event. This makes it impossible to remove the profiles from the event via the GUI.

This has been reported in a couple of forum threads, http://forum.civicrm.org/index.php/topic,8962.0.html and http://forum.civicrm.org/index.php/topic,8601.0.html

I wasn't able to successfully duplicate this issue on http://drupal.demo.civicrm.org/civicrm/admin/event?reset=1&action=update&id=1&subPage=Registration

I have seen it occur on multiple sites post-2.0 series (at which time I'm pretty sure I raised it with Lobo via IRC).

The workaround is to either install an innocuous profile and use that to replace the profile you want to remove, or to edit the entries in civicrm_uf_join.