If you turn on a section strategy and expect your lists to become grouped or you had them grouped and now they are not, here is what is going on:

We made it so you can always change the sections on the fly per list on the top right. 

So now when you want a list grouped you have to click the group by icon on the top right of the list you want to group:

You only have to do this once per list. 👍 You can also turn on multiple section strategies and switch between them or use different ones per list.