I have the following validation rule to prevent users from editing or creating products once the opportunity is won. The issue is that it can still be edited if they click on "edit all" in the opportunity object. Also, I would like to lock the "Quantity" and "Sales Price" once the opportunity is won. How can I do that? The code below prevents everything in the product from being edited after the opportunity has been awarded.
OR( ISPICKVAL(Opportunity.StageName, "WON"), ISPICKVAL(Opportunity.StageName, "LOST") )