Wrapping a ``RecyclerView`` with a ``NestedScrollView`` breaks its recycling
functionality because the view height is stretched to fit the full list
of entries.
We never noticed performance issues in these two cases because these
lists never get very long. Let's fix these cases anyway so that we
don't accidentally base a new use of a ``RecyclerView`` on this broken
pattern.
Also renamed ``list_slots`` to ``list_groups``. Must have been
a copy-paste error.