code: function renderDayOverlay(overlayStart, overlayEnd, refreshCoordinateGrid) { // overlayEnd is exclusive
  
  		if (refreshCoordinateGrid) {
  			coordinateGrid.build();
  		}
  
  		var segments = rangeToSegments(overlayStart, overlayEnd);
  
  		for (var i=0; i<segments.length; i++) {
  			var segment = segments[i];
  			dayBind(
  				renderCellOverlay(
  					segment.row,
  					segment.leftCol,
  					segment.row,
  					segment.rightCol
  				)
  			);
  		}
  	}
docs: /* Semi-transparent Overlay Helpers
  ------------------------------------------------------ TODO: should be consolidated with AgendaView's methods