Delete records in subform when one record is deleted in main form

Delete records in subform when one record is deleted in main form

Hi, 

I've a form (Form A) that create records in another form (Form B) when I submit the record in Form A, I've inserted the main form ID to each rows of the records I created in From B.

I created a delete record workflow on Form A to delete records in then in Form B using the record ID:

delete from FormB[FormA_ID = ID];

But it seems does not work when we deleted the record in Form A.

I change the criteria to loginuser:

delete from FormB[Added_User = zoho.loginuser];

This scripts works as it does delete all the records.

Just wonder why the deleting records using the ID does not work?

Thanks in advanced!