- Enter the distance you want to lengthen an entity by in the options
    tool bar. A positive value lengthens the entity, while a negative value
    shortens it. E.g. a value of '5' will lengthen the chosen entity by 5
    units.
- Choose the entity to be lengthened or shortened somewhere close to the
    end you want to modify.
- Right click or press the Escape key to terminate the tool.
  