I have two divs, first (Product Navigation) and secondly (Drop Down Wrap). When you click on Product Navigation it reveals the Drop Down Wrap. The Drop Down Wrap has a initial appearance of 0 Height and Display None and when the Product Navigation is clicked the Drop Down Wrap height=auto and display=block.
On the reveal, the drop down appears fine and smooth. On second click it closes most of the way smoothly then 'snaps' the rest of the way. Previously, I have changed the Overflow to hidden and has fixed this but it doesn't seem to work for this.
Please see the link below.
I hope this makes sense!