rem: if (this.popup != null) { this.layer.map.removePopup(this.popup); 
add: if ((this.layer != null) && (this.layer.map != null)) { if (this.popup != null) { this.layer.map.removePopup(this.popup); } 
context:     destroy: function() {        //remove the popup from the map        if (this.popup != null) {            this.layer.map.removePopup(this.popup);        }        this.events = null;        this.layer = null;        this.id = null;        this.lonlat = null;        this.data = null;        if (this.marker != null) {            this.marker.destroy();            this.marker = null;        }        if (this.popup != null) {            this.popup.destroy();            this.popup = null;        }    },
meta: 4411	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/4411/d5b5a8e8f03c0bcf5223cc11fae6dc6787a5f2f2/Feature.js/clean/lib/OpenLayers/Feature.js