code: function(oThis, sDir, bUpdateFocus){
  		RoadMapRenderer.scrollToNextStep(oThis, sDir, function(sFirstVisibleNodeId){
  			var iIdx = sFirstVisibleNodeId.lastIndexOf("-expandend");
  			if (iIdx != -1) {
  				sFirstVisibleNodeId = sFirstVisibleNodeId.substring(0, iIdx);
  			}
  			oThis.setProperty("firstVisibleStep", sFirstVisibleNodeId, true);
  
  			if (bUpdateFocus) {
  				refreshFocus(oThis, sDir);
  			}
  		});
  	}
docs: Helper function to scroll to following step (optionally with updating the focus (see focusStep)). Allowed directions are: next, prev, first, last.