Here you can activate the expert options. Field lengths can be changed in the Themes Manager with this setting.
In the options, you can also activate the Database dependent case sensitivity when filtering. If
this setting is active, the database will be case sensitive. When the
setting is not active, the filter will function independent of upper or
lowercase spelling, meaning that an entry of "a" will create hits that
contain a lowercase "a", but also hits with an uppercase "A".