Using parameter

I have two browser screens for sales order and customer. None of those screen has any filter used. However, when I want to display the list of sales orders from customer browser screen, I want the sales orders to be filtered by the selected customer. This means, the sales order browser screen will contain all data or filtered data (by customer) depending on whether it is called from customer browser screen or directly from the menu. A code example will help.

See Screen Manipulation example. The ProductBrowse screen modifies its datasource query depending on passed customer. If a customer is provided, the table shows only products for this customer and those without reference to a customer.