Afaik the drag drop in sortable list relies on distance, rather than
which element you are dragging over. drag_to might not work in that
case. A colleague of mine did something with drag_by, which is an
internal Selenium method that Capybara does not diectly expose (call
fint('foo').native.drag_by). It's all a bit tricky, I don't think he
got it working very well.