Try a calculation field in the parent table (Invoices?) =
Sum ( LineItems::LineItemTotal )
In the LineItem table, define a summary field as "total of" LineItemTotal.
In the parent table (The one your layout refers to in Layout setup...)
Define a calculation field as Sum(PortalTableOccurrence::LineItemTotal)
The second field, in my experience, updates a bit better when you need to put a "portal total" on your layout below the bottom of your portal. The other field is good for putting in reports based on your portal's table.
The Sum ( ReturnLineItems::LineItemTotal ) works when calcualting the first line item of my portal when I fill it out, but it doesn't notice/calculate any data added to subsequent lines. I toggled the storage option on & off with the same results.
In which table did you define this calculation field?
It should be defined in the Parent table not the portal's table.
The calculation using Sum(ReturnLineItems::LineItemTotal) should be defined in Returns.
Aggregate functions such as Sum, when used in this fashion, are computing a total of all records in the child table (ReturnLineItems) that are related to the current record in the Parent table (returns).
Beauty! That did the trick. Thanks!