rem: unregisterEvent("mousedown", digilib.scalerImg, zoomStart); 
add: unregisterEvent("mousedown", _this.scalerImg, zoomStart); 
context:     function zoomStart(evt) {        pt1 = evtPosition(evt);        unregisterEvent("mousedown", overlay, zoomStart);        unregisterEvent("mousedown", digilib.scalerImg, zoomStart);        // setup and show zoom div        moveElement(zoomdiv, Rectangle(pt1.x, pt1.y, 0, 0));        showElement(zoomdiv, true);        // register events        registerEvent("mousemove", document, zoomMove);        registerEvent("mouseup", document, zoomEnd);        return stopEvent(evt);    }
meta: 7747	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/7747/f14ff3764f1dfd4451016c594c8e1cad5907de5a/dllib.js/buggy/client/digitallibrary/greyskin/dllib.js