For me, the biggest challenge in using FM 7 is getting my head out of six and into seven. You tend to analyze and attempt to resolve issues from a 'six' perspective. While the refresh of unstored calcs is problematic in seven, don't even go there. Define the calc as stored...
Use the "evaluate" function:
Evaluate("Amount - Sum ( CashReciepts::AmountCredit )";Amount)
Whenever the trigger value, Amount, in your parent file changes the calc will re-evaluate and refresh. If, in addition to "Amount", you need changes in the related file to also update the calc, you can add another trigger field that changes value whenever you add a credit line item to the related file via a scripted event. (The trigger fields for the evaluate function should be stored values in the parent table.)
Evaluate("Amount - Sum ( CashReciepts::AmountCredit )";[Amount;field2])
No preview mode, refresh or flush tricks are needed here...plus you may pick up other benefits in having the calc stored.
