When I click in any of the items in the 'USERS' list I get this error:
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: There is no such grant defined for user 'example@localhost' on host '%'
Or this one:
java.sql.SQLException: String 'longname@localhost' is too long for user name (should be no longer than 16)
I wrote a mail to Squirrel-sql-users list about this with the subject MySQL Plugin create database.