add: if (!gUpdateWizard.xpinstallEnabled) return;  
context:   onSelect: function (aEvent)  {    var updates = document.getElementById("found.updates");    var oneChecked = false;    var items = updates.selectedItem.getElementsByTagName("checkbox");    for (var i = 0; i < items.length; ++i) {        if (items[i].checked) {        oneChecked = true;        break;      }    }    var strings = document.getElementById("updateStrings");    gUpdateWizard.setButtonLabels(null, true,                                   "installButtonText", true,                                   null, false);    var text = strings.getString("foundInstructions");    document.getElementById("found").setAttribute("next", "installing");     document.documentElement.getButton("next").disabled = !oneChecked;    var foundInstructions = document.getElementById("foundInstructions");    while (foundInstructions.hasChildNodes())      foundInstructions.removeChild(foundInstructions.firstChild);    foundInstructions.appendChild(document.createTextNode(text));  }
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/056ac635694d68ac8ac7ddd8550b121b3d4a050c/update.js/buggy/toolkit/mozapps/extensions/content/update.js