Tracking vertically causes slider movement

[almstrand]

As demonstrated in this video:

https://drive.google.com/open?id=0BwGQxgIKSiNZaXYwVTBNbWRBVjA

on a touch-enabled device, touching near paper-slider and dragging mostly vertically (with little horizontal movement) causes the knob to move.

This is problematic when using paper-slider on a page that supports vertical scrolling. If the user taps near the element and drags vertically to scroll the page, the slider's knob can move and inadvertently change the value from what was previously selected.

As a possible solution, can the angle of the drag vector be calculated allowing the knob to snap back to its prior position should the angle be greater than a preset value, e.g. 45°?