add:  if (this.opacity != null) { marker.setOpacity(this.opacity); }  
context:     addMarker: function(marker) {        this.markers.push(marker);        if (this.map && this.map.getExtent()) {            marker.map = this.map;            this.drawMarker(marker);        }    },
meta: 4411	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/4411/0266041005521a13b4ab8f8ef4a55841edb84ddb/Markers.js/clean/lib/OpenLayers/Layer/Markers.js