Minimap: positioning vs ancestor tree

E.g. https://cdpn.io/pen/debug/oNOMRav has an animation on `.inner`. When inspecting it’s not correctly positioned in the minimap as the minimap does not take all intermediary elements between the element itself and the root.

In that specific demo it’s the intermediary `#wrapper` is fixed positioned.

Reproduce the issue using the linked CodePen, especially the animation on `.inner` with the fixed-position `#wrapper`. Trace how the minimap determines positioning relative to the root and account for intermediary elements in the ancestor tree. Done means the animated element is correctly positioned in the minimap in this example.

Written by the indexing model from the issue text.