Hi Ray,
Please try to work with it a couple of days if it’s possible for you, and then please tell if you still experience inconvenience.
For now menu is scrolling only within its own height. This means that when you are scrolling down menu will scroll until we reach its end, then you will see it sticky to the bottom. If you then start to scroll up, menu will follow your scrolling until we reach its top and then will stick to the top. A bit jittery effect is caused by browser default behavior during mouse wheel scrolling. If you try to drag the scroll thumb explicitly you will see more smooth scrolling of the menu as well as other part of the page.
I have discussed and tested this with my clients, and they are happy with the solution we have right now. If you are still unhappy with it, I’ll add another option that will make possible previous menu behavior.
Thank you for your patience and feedback!
-Nadia