Append(k1):Insert(k2) Viewable(k1):Hidden(k2)
- foobar_k2 should be directly to the left of artist
- foobar_k1 should be on the far right
- both foobar_k1 and foobar_k2 should be in the column picker for this page
- only foobar_k1 should be in the column picker for the main library
- BUG: neither splitter around k1 is resizable