Our users are having an issue deleting contacts from contact groups that they have created. This started happening since we upgraded to 5.0.6. Basically when a users clicks to remove a single user (internal or external), Firefox spits this out "A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete.
It fails in IE but IE just sits there and locks up and doesn't display any messages. I've tried doing this late at night when there is no load on the machine but a contact still won't delete. I have also removed some non standard zimlets and restarted Zimbra but that didn't help either.