--- a/toolkit/mozapps/extensions/test/xpinstall/browser_signed_multiple.js
+++ b/toolkit/mozapps/extensions/test/xpinstall/browser_signed_multiple.js
@@ -8,32 +8,45 @@ function test() {
   Harness.setup();
 
   var pm = Services.perms;
   pm.add(makeURI("http://example.com/"), "install", pm.ALLOW_ACTION);
 
   var triggers = encodeURIComponent(JSON.stringify({
     "Signed XPI": TESTROOT + "signed.xpi",
     "Signed XPI 2": TESTROOT + "signed2.xpi",
+    "Signed XPI 3": TESTROOT + "signed-no-o.xpi",
+    "Signed XPI 4": TESTROOT + "signed-no-cn.xpi",
+    "Signed XPI 5": TESTROOT + "unsigned.xpi"
   }));
   gBrowser.selectedTab = gBrowser.addTab();
   gBrowser.loadURI(TESTROOT + "installtrigger.html?" + triggers);
 }
 
 function get_item(items, url) {
   for (let i = 0; i < items.length; i++) {
     if (items[i].url == url)
       return items[i];
   }
   ok(false, "Item for " + url + " was not listed");
 }
 
 function confirm_install(window) {
+
+  var sbs = Components.classes["@mozilla.org/intl/stringbundle;1"].
+                       getService(Components.interfaces.nsIStringBundleService);
+  var bundle = sbs.createBundle("chrome://mozapps/locale/xpinstall/xpinstallConfirm.properties");
+
+  var expectedIntroString = bundle.formatStringFromName("itemWarnIntroMultiple", ["5"], 1);
+  
+  var introStringNode = window.document.getElementById("itemWarningIntro");
+  is(introStringNode.textContent, expectedIntroString, "Should have the correct intro string");
+
   items = window.document.getElementById("itemList").childNodes;
-  is(items.length, 2, "Should be 2 items listed in the confirmation dialog");
+  is(items.length, 5, "Should be 5 items listed in the confirmation dialog");
   let item = get_item(items, TESTROOT + "signed.xpi");
   if (item) {
     is(item.name, "Signed XPI Test", "Should have seen the name from the trigger list");
     is(item.cert, "(Object Signer)", "Should have seen the signer");
     is(item.signed, "true", "Should have listed the item as signed");
   }
   item = get_item(items, TESTROOT + "signed2.xpi");
   if (item) {
@@ -44,15 +57,15 @@ function confirm_install(window) {
   return true;
 }
 
 function install_ended(install, addon) {
   install.cancel();
 }
 
 function finish_test(count) {
-  is(count, 2, "2 Add-ons should have been successfully installed");
+  is(count, 5, "5 Add-ons should have been successfully installed");
 
   Services.perms.remove("example.com", "install");
 
   gBrowser.removeCurrentTab();
   Harness.finish();
 }

--- a/toolkit/mozapps/xpinstall/content/xpinstallConfirm.js
+++ b/toolkit/mozapps/xpinstall/content/xpinstallConfirm.js
@@ -79,17 +79,17 @@ XPInstallConfirm.init = function ()
     else {
       installItem.cert = bundle.getString("unverified");
     }
     installItem.signed = args.installs[i].certName ? "true" : "false";
   }
   
   var introString = bundle.getString("itemWarnIntroSingle");
   if (numItemsToInstall > 4)
-    introString = bundle.getFormattedString("itemWarnIntroMultiple", [numItemsToInstall / 4]);
+    introString = bundle.getFormattedString("itemWarnIntroMultiple", [numItemsToInstall]);
   var textNode = document.createTextNode(introString);
   var introNode = document.getElementById("itemWarningIntro");
   while (introNode.hasChildNodes())
     introNode.removeChild(introNode.firstChild);
   introNode.appendChild(textNode);
   
   var okButton = document.documentElement.getButton("accept");
   okButton.focus();