docs: function drawSelection(dataArray) {
  		var firstItem = (dataArray && dataArray.length > 0 ? dataArray.slice(0, 1) : []),
  			firstItemX = (dataArray && dataArray.length > 0 ? valueX(dataArray[0]) : 0),
  			lastItemX = (dataArray && dataArray.length > 0 ? valueX(dataArray[dataArray.length - 1]) : 0),
  			width = (lastItemX - firstItemX) + xBar.rangeBand();
  		var selectBar = parent.svgHoverRoot.selectAll('rect.selectionbar').data(firstItem);
  		selectBar.attr('x', firstItemX)
  				.attr('width', width);
  		selectBar.enter().append('rect')
  				.attr('x', firstItemX)
  				.attr('y', 0)
  				.attr('height', parent.height)
  				.attr('width', width)
  				.classed('selectionbar clickable', true);
  		selectBar.exit().remove();
  	}