Getting Started with the New Purview eDiscovery (E3)

Thanks for a great introduction to the Purview! I wondered if you could address how the Hold interacts with the Search. In the old Purview interface, you would create a Hold, then in the Search you could indicate that it should search "Locations on Hold", which made sense. In the new Purview, even after I've created a Hold, the Search "Add a Source" section doesn't seem to have any way to add those already-on-hold locations, which doesn't make sense.

I do have a grayed-out button in the Add a Source dialog that says "All Sources in this case" (see screenshot below), but it's not available to choose. I shouldn't have to go through the (very slow) process of selecting the sometimes large list of users first for the Hold, and then do the exact same thing again in Search....the users selected in Hold should be available to Search, just like the old Purview.

Am I missing something? Thanks!