rem: return this.getButton() == "left"; 
add: return this._buttonLeft; 
context: proto.isLeftButton = function() {  return this.getButton() == "left";};
meta: 1005	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/1005/d0984a49e5708d61cfe1e6165e1e198760df5324/QxMouseEvent.js/buggy/qooxdoo/source/script/events/QxMouseEvent.js