A gesture helper should only take care of interpreting "pointer(s)" movements.
The UI logic that takes care of actually dragging elements underneath when a "pan" gesture is detected, is implemented in the ViewPager.
Infact, if you look at the view_pager.js source code, you'll notice that it is using the gesture_helper to do its job.
https://genielabs.github.io/zkit/docs/controllers/view_pager