Sprite Atlas v2 doesn't work at all

I’m trying to create a sprite atlas and when I click “Pack Preview” nothing at all happens - the button just gets grayed out. I’ve tried with one or multiple sprites added to “Objects for Packing”.

The sprites are Sprite (2D and UI), Single, with no compression. There are no errors in the console.

I figured it out. For some reason, the Pack Preview window is hidden at the bottom of the inspector (you have to drag the double line bar up to show it), and there’s no other indication of whether packing succeeded or failed; so it looks like the whole thing is just broken.