[GNC] Possible Bug in Credit Note Display

[Robert Simmons]

> I cannot duplicate this on v4.11 running on BigSur.

This happens in macOS and in Linux. Here are the steps to reproduce. You
will need at least one vendor existing to do this. If you have no vendors,
create one called "Acme".

1. Business menu > Vendor > New Bill...
2. Type: Credit Note
3. Vendor: Acme (or one of your existing vendors)
4. OK
5. Description: Widget (this doesn't matter)
6. Action: Material (this doesn't matter)
7. Expense Account: Expenses:Books (this doesn't matter)
8. Quantity: 1
9. Unit Price: 100
10. Hit enter to enter this row.

If you are on linux, there are two rows drawn in the UI. One empty at the
bottom and one populated with data. If you are on macOS, there is one row
populated with data.

Now, select the row populated with data and observe the subtotal column.

BTW: I bet the reason you can't reproduce this is you didn't create a
credit note. You probably created a bill where this software defect does
not occur.