code: function(){
  		if(!this.enableUndo){ return false;}
  		var opes = this.history[this.position-1];
  		this.reqReset = this.checkReqReset(opes);
  		this.preproc();
  		this.undoCore();
  		this.postproc();
  		return this.enableUndo;
  	}
docs: --------------------------------------------------------------------------- opemgr.undo()  Undoを実行する opemgr.redo()  Redoを実行する ---------------------------------------------------------------------------