Format control validation

Hi experts.


I have fields "priority" and "importance".

Values are stored in global lists $G.prior under values:







now I have in incident management format control give a validation that there is no possibility tu put other values than this which are stored in global list. So there should be no possibility to save new incident, or update existing if in any case somebody or somewhow there will be values for example 5.


So I figure out some comparision curent value to the global list value.


So I want to use function index




Where tu put this validation or how it should look like ? In add,update,delete ? in which conditions ?

how to bite it ? please help.


Best regards