Error when draggable point is clicked

[ghost]

When the user clicks on a point that has been defined as draggable, the following error is produced:
draggable-points.js:96 Uncaught TypeError: Cannot set property 'dragStart' of undefined

[pawelfus]

Demo for the issue: http://jsfiddle.net/highcharts/AyUbx/ (official one). Issue comes from this line. I think there should be else case to return an empty point, or simply define newPos = {} here.

[ghost]

Here's a patch that solves the issue by checking for the state of the point inside the event handlers (I had to zip it as github apparently doesn't support .patch extension).
diff.zip

[meng-du]

I think this should have been fixed by PR #54 (merged)