taxonomy drag & drop not properly disabled for multiple parent vocabs

When I set multiple parents to a term I get this warning:

> Adding multiple parents to a term will cause the Tags vocabulary to look for multiple parents on every term. Because multiple parents are not supported when using the drag and drop outline interface, drag and drop will be disabled if you enable this option.

(Which, BTW, has problems of its own: #949616: Multiple parent relations confirmation form loses term description)

However, on saving, the term list page still has drag handles on the terms, even though there is no button to save changes.