[moveColumn] shadow incorrectly positioned

[AgDude]

http://plnkr.co/edit/FmP0owXifzaPcFSRyuCO?p=preview

Move column works fine in the main render container, but trying to move columns within the left container doesn't show the shadow.

[AgDude]

The following scenarios cause the movingColumn div to be incorrectly positioned, beginning with a negative "left" style.

• Moving in a container (original issue)
• Move column while the grid is scrolled to the right.
• Using a touch device - This seems to be related, but I don't have a good answer as to why. on ipad using both safari and chrome, the shadow is rendered off the left side of the grid (hidden), but if you drag far enough to the right it comes into view.