HistCopy

HistCopy = Yes | NO:  Controls what happens when you re-execute a line 
from the command history.  If this option is set to Yes, the line is 
appended to the end of the history list.  By default, or if this option is 
set to No, the command is not copied.  The original copy of the command is 
retained at its original position in the list, regardless of the setting 
of HistCopy. 

Set this option to No if you want to use HistMove = Yes; otherwise, the 
HistCopy setting will override HistMove.