Hi,
select the dimension so it is highlighted
-- RMB --> Properties
-- Terminator and Symbol
Display -> set to either Origin or Measurement
-- Lines and Coordinate
Projection Line -> set to either Origin or Measurement
OK
-- with the dimension still selected 'grab' the black handle
at the free end (cursor should change) and move it to a
position you want it
Origin = the end that is connected to the first line
selected
dy