When I validate line on item sublist for a field

function drawVerifyValidateLine(type) {

if (type == 'item') {

var isVerified = nlapiGetCurrentLineItemValue('item', 'custcol_drawing_verification');

if (isVerified !== 'T') {

alert("You must check drawing verification for this service item.");

return false;

}

return true;

}

}

This works , but there is another custom sublist in custom tab, that misbehaves due to this. I am not able to add item in that custom list(add operation is rejected). When I undeploy my client script (code above), this custom sublist again starts working normally. What am I doing wrong ?

you should return true outside of the if

ohh, I got it. Thanks a lot @mizax, have a good day !