Slider doesn't slide back if mouse is released
I built an interaction where the learner uses a slider to move a picture of an old historical site over the present day site. The slider works perfectly moving back and forth as long as the learner doesn't release the mouse button. However, if the learner releases the mouse in mid-slide or once the slider is fully completed, the learner can't slide back and forth again.
I feel like this must be a REALLY easy setting or trigger to resolve this but I can't seem to figure it out.
Link to the interaction: