Select Multiple Files

This is pretty trivial, but I can’t figure it out. We just upgraded to 8.5.1 FP3 from 6.5.6. In the 6.5.6 admin client, in the files tab, I could select multiple files by holding down the ctrl or shift key. I can’t do it in the 8.5.1 admin client, with either key.

What am I missing?