maybe here before trying to answer of this question we need to clarify the real intention behind your question.
On which device should the dragging work?
So on HoloLens and on mobile devices we do not have a mouse. If we need to drag a label, how to define the start and how to define the end of the dragging ( e.g. by command "start dragging" and "end dragging" on the HoloLens or on Mobile Device by tap on the label)
In generally I think that could be possible but need more deeply check which system events should be used.
On the HoloLens we could try to use the gaze vector of the tracking event
But on the mobile device I think it will be more difficult -> we can try to use the click event which could get the 2d panel coordinates of the click and then try to calculate the 3d movement