content zones - Iprocurement -r12

 Hello 

I am struggling a bit with the content zones;

I just want to knowwhat  the difference is in search if I set

- include items without suppliers

       - this will give me all internal orderable items; also items on req templates and items with a purchasing category assigned

and include items from all categories ?

   - this will also give me that same as above -- (only not the ones whihc are on a req template)

         and all items assigned to a purchasing category 

this is not really clear to me..  

(so if I have a content zone with all these checked (inlude items from all suppliers, include without suppliers, include from all categories ) --> which items will I see ??(assumming attached to a store etc)