Searching on Receipt Sent=null should only return entries with contributions and unsent receipts

Using the demo site I played around with the contributions module and searching for individuals with unsent receipts returns a list of individuals without contributions as well as those with contributions for which the receipt has not yet been sent out. Indivdiuals without receipts should be filtered from this list. Ideally, the 'hasReceivedReceipt" should be an attribute of the donation and not the individual.