Due to a problem with the Frame Buffer II IP core when Module is Frame Writer only is selected, you cannot change the Maximum ancillary packets field. That field, under the Memory section of the parameter editor, will be greyed out and not editable.
Frame buffer in frame writer mode, default Ancillary packets = 0
This field defaults to 0 (zero), which will cause all ancillary packets (also known as User packets) to be dropped.