keyboard navigation makes calendar unresponsive

AngularJS v1.2.27 - maybe this is the problem, but the requirements aren't in the readme, so I'm not sure.

Anyway, when I focus the input and use an arrow key, nothing happens. I can no longer use the mouse to pick a date or clear.

Eventually, Chrome (Version 39.0.2171.71 (64-bit)) says some pages have become unresponsive, Kill Pages or Wait.