Hi,
Generally if you try to pull out a sales order by giving the Delivery Block option as in the sales order, IT will bring that sales order in the output screen. However, we will not be allowed to priocess the Shipping activities for the sales order. I have simulated the same in my sandbox system.
The buttons in the "Blocked Deliv. Not Selected" are related to the Exclide options in the Delivery Block field in the screen.
Regards