When attempting to change a user's details (host for example) by selecting to "delete the old one from the user tables." I keep getting errors such as:
---------------------------------
DROP USER 'testuserlocalhost'@'';
MySQL said: Documentation
#1470 - String 'testuserlocalhost' is too long for user name (should be no longer than 16)
---------------------------------
DROP USER 'testuser%'@'';
MySQL said: Documentation
#1396 - Operation DROP USER failed for 'testuser%'@''
Bug confirmed for 3.2.0.
Fixed in subversion, thanks for reporting.