Bug: 4.0b Beta 9: Sort Library by Tags column doesn't work -- sorts by Title

Open Library, make sure Tags column is visible (not My Tags, but just regular Tags).

Click on Tags column header to sort by it.

Result: library sorts by Title, not by Tags.

Note: My Tags works fine. It sorts/groups by tags I've assigned. I'd expect Tags to work the same way.

[I realize Tags is a field that is being reserved for future use, but for now it does show the tags I've assigned. So I would expect some sort of sensible behavior when sorting by that column. The way it behaves now is clearly wrong.]