RailwayRouteOptimization/scripts/Draw/Dimension/Leader/doc/Leader_proc_ru.html

<ol>
  <li>Set the location where the leader points to or enter a coordinate in the
  command line.</li>
  <li>Set the location of the next edge of the leader line.</li>
  <li>Set the other edges of the leader line and click the
  right mouse button or press the Escape key to finish.</li>
</ol>