If an account has not been paid, it will be shown in Tab.
You will notice the Amount field in the main window will change to the total figure of the accounts you have selected to pay.
If you attempt to select a record via the select column for which monies have not been receipted, you will be informed that no monies have been receipted and the record will automatically be unselected.
If you specifically need to pay a record which has not been receipted, you must physically type the amount being paid into the amount column. You will then be provided with a warning that you are self funding that amount due to no monies being received.