A user deleted the SalesTaxCode field from the SalesOrderLine grid on the stock Sales Order screen. Tax calculation on this screen relies on this field so they asked how to add it back.
The first step is straight forward, simply edit the grid and insert the SalesTaxCode field on Step 2 of 9 of the Grid Wizard. The second step is a little more tricky. There are some actions on the Item field in the grid that enter the related SalesTaxCode values when you select the item (in the Text Change event). See the screenshot below to learn how to find these actions:
In the third window (far right) of the screenshot, make sure the SalesTaxCode is placed into the SalesOrderLine:Sales Tax Code column on the grid. This connection may have been broken when the field was deleted. Please reply on the forums if you need more help!
Jason