Patch to jqlot's highlighter plugin to support arbitrary strings on highlight tooltips. This patch implements the work done by Chris Folger on an older version of the plugin: http://www.cefolger.net/2011/04/enabling-jqplot-highlighter-to-use-tick.html ALso includes a workaround for a bug in jqplot that breaks tooltips on plots with null points. Patch is against jqplot 1.0.0b2_r792.