When configuring LDAP integration, writing complex filters for the 'Group Object Filter' and 'User Object Filter' fields is difficult at present because the fields only allow about 30 characters. Because the fields have the same design, I'd find it more user friendly if they were all widened to 120 characters or more.

The Configuration tab is displayed at http://confluence.atlassian.com/display/CROWD/Configuring+an+LDAP+Directory+Connector#ConfiguringanLDAPDirectoryConnector-ConfiguringLDAPObjectandAttributeSettings