Groups are not Selectable

I'm using Using v10.0 x64 on Windows 10.
GROUPSELECT is ON and I've tried toggling it.
My groups are showing in the list. But when I try to select a group, only a single entity selects, not the whole group.
I've used groups in the past with out any problems. I feel like I must be missing something. Are there other things controlling this behavior?