We wanted to change the default names of groups that come with JIRA 1.4.3. So I exported the data, and did a global search and replace of all instances of "jira-developers" with "Developers". Then I imported the data.

When I do this, I can see the "Developers" group from the group browser list, but if I try to view the users in this group it is blank.

Also, if you try to edit groups for a user, you'll see all your group names in the two membership lists (for join and leave), but when you try to add a group, an exception will be thrown.

To fix, I had to go in and rename the "Developers" group to "developers" and it works fine. Looks like certain parts of the app are coded to use a lowercase group name, and mixed case group names throw it off.