Selecting a group is hard

[maxkfranz]

Describe the bug
A clear and concise description of what the bug is.

It's hard to select a group.

(1) User perspective: How do you select a group? I tried clicking, just like you can click other nodes, and nothing happened.

(2) Drag selecting a group is difficult, because I usually select other nodes outside the group too.

To Reproduce

Just open a network.

Expected behavior
A clear and concise description of what you expected to happen.

Clicking to expand or collapse a group should select it.

[mikekucera]

We discussed auto-selecting all the nodes in a cluster every time its expanded.