While implementing a component called VirtualList to encapsulate the rendering and resize observer logic, I came across the scroll sizing problems where the scroll bar would always assume more items then there actually are and hence be very small in size. Eventually upon scrolling the size resets but that produces a very sluggish interaction when scrolling.

The possible problems that I looked at were memoized render props not getting updated or estimates sizes being totally off but none of them were the issues here. I or someone will have to spend some more time understanding why that is the case so that we can unify the duplicate list into one common component.

The WIP can be found in the attached branch here.