well, in all my plays, i never had the ammount to turn back on my reaction-fire if i moved my soldier farther then i could without deactivating the mode...
so, personally... i see no sense in this request since the outcome would be, the soldier can not reactionfire anymore in that turn if he moved to far
what you suggest is a bit weird, you know? nobody needs to deactivate reaction-fire to move the soldiers around @_@ but you say you do that allways it seems, just to reactivate it again *is confused*