add:   if (this._downloadStatus.textContent == status) return; 
context:   _setStatus: function(status) {    while (this._downloadStatus.hasChildNodes())      this._downloadStatus.removeChild(this._downloadStatus.firstChild);    this._downloadStatus.appendChild(document.createTextNode(status));  },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/73531d421cf5053df3593f811960ff9c19b843ad/updates.js/clean/toolkit/mozapps/update/content/updates.js