Relayout'ing orientation of scrollable legends is off  

See http://codepen.io/etpinard/pen/oLPpkj

In detail:
- going from `legend.orientation` `'v'` to `'h'` does not remove the scroll bar
- going from `legend.orientation` `'v'` to `'h'` does not remove the scroll handlers
- going from `legend.orientation` `'h'` to `'v'` does not add a scroll bar immediately (the scroll bar appears only after attempting to scroll).
