Symptoms

Once a directory has been set to bind with a username/password, it is not possible to set it to anonymous bind.

Steps to reproduce

1. Set up an LDAP server that allows anonymous bind
2. In Crowd, create a new connector, set an invalid username and password.
3. Save the new connector. Test the connection. It should fail because of the invalid username and password.
4. Go to Update connector to change its configuration.
5. Clear the username field (the password field is already empty because the existing password is not revealed).
6. Submit the form and test the connection again.

Expected behaviour

The test should pass, because the directory is configured to use anonymous bind.

Actual behaviour

The test fails, because the directory configuration still retains the old password.