Cappuccino Cappuccino

Improve token field keyboard navigation when tokens are selected.

If one or more token is selected and the left arrow key is pressed, collapse the selection to the left of the first selected token.

Similarly, on right arrow key collapse to the right of the last token.

Note that shift-left and shift-right have no effect if the first or last token respectively in the field are already selected.
https://github.com/cappuccino/cappuccino/commit/d39849b297bfeed3f3d...