Normally, Gestix considers all sales documents as sales. To select which documents are considered as sales and which document are not, on the Customers menu tap the Sales Filter button.
![Tap the Sales Filter button to open the selection window](https://blog.gestixsoftware.com/wp-content/uploads/2014/10/sales-filter-button-gestix.jpg?w=300)
You are then able to specify which documents to consider by selecting/deselecting their series on this screen.
![(Leave all blank to let Gestix automatically select the pertaining documents)](https://blog.gestixsoftware.com/wp-content/uploads/2014/10/sales-filter-in-gestix.jpg?w=300)
Either place a check mark in every document to be considered or leave all unchecked for enabling Gestix to select automatically all the sales documents.
(The same principle applies to suppliers/vendors accounts in Gestix, but concerning purchase documents instead of sales documents.)