Indicate Position in Elevation Plot when Hovering Over Map

[wp99cp]

If you hover over the elevation plot, you can see the current cursor position in both the map and the elevation profile. However, the other way around, you can see it only on the map and not inside the elevation plot.

Hovering over the map and elevation plot should have the same result as seen in the following screenshot:

[maede97]

This is still open for TODO (also with the latest addition of editing the selected POIs.