The issue JRA-28788 was raised as Labels could not be inline-edited on the view-issue page if the Labels field was not in the Edit Screen. In previous versions of JIRA it was possible to edit the labels field even if the field was not present in the Edit Screen.

It has been decided not to restore this behaviour in JIRA 5.1 and beyond so an alternative to inline editing Labels needs to be documented.

There are two options:

1. Press the 'l' key to bring up the Labels dialog
2. Add the Labels field to the Edit Screen

Further, to increase visibility of the issue, it was proposed that the JIRA Admin Helper Plugin be used to help diagnose why people cannot edit a particular field. Currently the plugin does not load the Edit Screen details on the View Issue page. I will raise an issue with the developer to see if this is possible.