If you want to select a result set (checking the boxes on the left of the list) then you can check the box on the header, which will select just those in view and present you with a count and a link to select the whole result set.
If you mean display them all so you can keep scrolling and scrolling like we used to do in v11, I don't believe that is an option anymore, but I have had several users request that so I'll be curious to see if someone has something that works.
