Fields that you select here are displayed as columns of search results for the action view that has this default action type set. Those action views with a business function tabbed form will also show the grid fields set for their default action type. In order for this to occur, the fields must be marked as ‘Visible’ at the Options tab.
Check the boxes of all fields that are to appear. You can also click 
and 
to change the position of a field within the search screen or tabbed form.