public static FilterFieldDefinition qualifiedField(final String displayName,
                                                       final String filterQualifier) {
        return new FilterFieldDefinition(displayName, filterQualifier, false);
    }
Creates a field that has to be qualified, e.g. 'type:error'

@param displayName     The display name or column heading for the field in the table.
@param filterQualifier The custom field qualifier used in the quick filter. Only use this if you want a
                       qualifier that is different from the display name. Should match ^[a-zA-Z0-9]+$
stroom-util-shared/src/main/java/stroom/util/shared/filter/FilterFieldDefinition.java