By removing attributes from the
OrdersView view object you have reduced the number of columns in the view object's query.
When creating your client user interface you have another opportunity to choose which of the remaining attributes to show on the client page, but it makes sense at this stage to remove attributes that will not be used in any client.
The Attributes page in the overview editor displays the attributes that remain in the
OrdersView view object, after unneeded attributes are deleted.