[Koha-devel] needed help in koha cataloguing module

Dear all, i am using koha 22.11 version i want to disable the indicator box and box for (a) (b) (c) etc so user can not type and change the [a] [b] [c] to [e] [f] [3] etc. On adding/modifying books koha page koha/cataloguing/addbiblio.pl when i click on 245 (*a*) it allow me to change (*a*) i want to disable/readonly [a] and two boxes for indicators so it cannot be changed.is there any system preference value to restrict the user? or any other suggestion? should i look into MARCOverlayRules ? needed help in this problem. Best regards, -- *Zahid*