On iPad, and presumably any touch device, the window x and y coordinates provided during a drag are NaN. For now, prevent a crash.
On iPad, and presumably any touch device, the window x and y coordinates provided during a drag are NaN. For now, prevent a crash.

concord-consortium/codap,concord-consortium/codap,concord-consortium/codap,concord-consortium/codap,concord-consortium/codap