How Do I Prevent Attributes From Being Copied into New List Elements?
The system automatically copies key fields (based on name matching) from a parent list element into new child elements (e.g. created by using the scroll '+' button), in order to keep their prime keys consistent. If you want to inhibit this operation for certain fields, define the TabMenu function dontCopyKeyNames_​<LIST NAME> to return an array of fields that should not be copied into new elements of the list named LIST_​NAME
Example:

function dontCopyKeyNames_ENRL_FLD() {
   return ['SEQ_NUM']
}