Removing handle breaks track styles

I am using range with multiple handles and track styles. After first rendering the slider, the props for the handles and track styles may change. ie. the user may click a button to remove a handle from the slider. I also adjust the track styles to compensate for this change. However, there is a bug in the rendering of the track styles. When I remove a handle the trackstyles can get out of sync. I have been able to work around this bug by adding a key equal to the number of handles. This work around makes keeps the track styles in sync with the handles, but it of course causes unnecessary work for react in dismounting and remounting the component and is a poor use of a key prop.

Start by reproducing the issue with a range slider using multiple handles and track styles, then change the handle props and styles after the first render. Trace the track-style rendering and handle-update path; done means styles remain aligned after a handle is removed without requiring a key that remounts the component.