RouteConverter displays positions in three different views: a map, a position list and an elevation and speed profile. Each of these views allows to select a position which is immediately reflected in the other views:
Selecting positions in the map works best for tracks and waypoint lists as a left click just needs to be in a circle of 15 pixels around the position to be selected. RouteConverter then selects the closest position found in that circle. For routes, this doesn't work reliably since it's possible to drag between two positions to create a third intermediate position.