private void scrollLeft( int move) {
		int lgth=timeLineObject.displayEnd-timeLineObject.displayStart;
		if( timeLineObject.displayStart-move<=0 ){
			timeLineObject.displayStart=0;
			timeLineObject.displayEnd=lgth;
		} else {
			timeLineObject.displayStart-=move;
			timeLineObject.displayEnd-=move; 
		}
	}