When using pulse width trigger on the DPO4000/MSO4000+ why does the trigger indicator not line up with the start of the pulse?

When using pulse width trigger on the DPO4000/MSO4000+ why does the trigger indicator not line up with the start of the pulse?

The trigger lines up with the end of the pulse. The oscilloscope must first find a pulse that corresponds to the trigger conditions set, and at that point triggers the scope.