Table View, sort on a calculation: bug or missing feature?

Easy situation:

Table A: invoices

  • id
  • invoice_total (calculation: invoices_rows.total)

Table B: invoices_rows

  • id
  • id_invoice
  • q.ty
  • price
  • rowtotal (calculation: q.ty*price)
  • total (sum: rowtotal)

Relation: tableA(id) → tableB(id_invoice)

If I build a form in TableA with the ‘invoice_total’ column and switch to table mode I cannot sort clicking on the column header but if i call the sort dialog and select the related column ‘total’ it’s okay (it’s quite slow anyway).
Is this an expected behaviour or a bug?
Will it make a difference if I store the calculation for invoice_total in table A?
I’m using 2.2b1 but I dont know if this was also present in stable version.

Nick

yes, make the calculation stored!