This is not working.  I tried going to a private window, the same thing happens.  I have an invoice for $400 that the customer paid $100 reducing the balance of the invoice to $300.  Then we issued a credit memo $300 to clear the balance of the invoice.  When I go to "Receive Payment" and I select the invoice with a balance of 300 and the credit memo for 300, the "Amount Received" at the top shows 300.  If I change it to 0.00 then it says this will create a credit transaction in the amount of 300. I'm totally lost.