diff --git a/lib/sdk/test/runner.js b/lib/sdk/test/runner.js
index b1bc355dc..4db9acae3 100644
--- a/lib/sdk/test/runner.js
+++ b/lib/sdk/test/runner.js
@@ -10,6 +10,18 @@ var cfxArgs = require("@test/options");
 var { Cc, Ci}  = require("chrome");
 
 function runTests(findAndRunTests) {
+  var ww = Cc["@mozilla.org/embedcomp/window-watcher;1"]
+           .getService(Ci.nsIWindowWatcher);
+
+  let ns = 'http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul';
+  let msg = 'Running tests...';
+  let markup = '<?xml version="1.0"?><window xmlns="' + ns +
+               '" windowtype="test:runner"><label>' + msg + '</label></window>';
+  let url = "data:application/vnd.mozilla.xul+xml;charset=utf-8," + escape(markup);
+
+
+  var window = ww.openWindow(null, url, "harness", "centerscreen", null);
+
   var harness = require("./harness");
 
   function onDone(tests) {
@@ -17,6 +29,7 @@ function runTests(findAndRunTests) {
     var total = tests.passed + tests.failed;
     stdout.write(tests.passed + " of " + total + " tests passed.\n");
 
+    window.close();
     if (tests.failed == 0) {
       if (tests.passed === 0)
         stdout.write("No tests were run\n");
@@ -27,22 +40,34 @@ function runTests(findAndRunTests) {
     }
   };
 
-  // We may have to run test on next cycle, otherwise XPCOM components
-  // are not correctly updated.
-  // For ex: nsIFocusManager.getFocusedElementForWindow may throw
-  // NS_ERROR_ILLEGAL_VALUE exception.
-  require("../timers").setTimeout(function () {
-    harness.runTests({
-      findAndRunTests: findAndRunTests,
-      iterations: cfxArgs.iterations || 1,
-      filter: cfxArgs.filter,
-      profileMemory: cfxArgs.profileMemory,
-      stopOnError: cfxArgs.stopOnError,
-      verbose: cfxArgs.verbose,
-      print: stdout.write,
-      onDone: onDone
-    });
-  }, 0);
+  // We have to wait for this window to be fully loaded *and* focused
+  // in order to avoid it to mess with our various window/focus tests.
+  // We are first waiting for our window to be fully loaded before ensuring
+  // that it will take the focus, and then we wait for it to be focused.
+  window.addEventListener("load", function onload() {
+    window.removeEventListener("load", onload, true);
+
+    window.addEventListener("focus", function onfocus() {
+      window.removeEventListener("focus", onfocus, true);
+      // Finally, we have to run test on next cycle, otherwise XPCOM components
+      // are not correctly updated.
+      // For ex: nsIFocusManager.getFocusedElementForWindow may throw
+      // NS_ERROR_ILLEGAL_VALUE exception.
+      require("../timers").setTimeout(function () {
+        harness.runTests({
+          findAndRunTests: findAndRunTests,
+          iterations: cfxArgs.iterations || 1,
+          filter: cfxArgs.filter,
+          profileMemory: cfxArgs.profileMemory,
+          stopOnError: cfxArgs.stopOnError,
+          verbose: cfxArgs.verbose,
+          print: stdout.write,
+          onDone: onDone
+        });
+      }, 0);
+    }, true);
+    window.focus();
+  }, true);
 }
 
 function printFailedTests(tests, verbose, print) {
diff --git a/test/test-window-utils.js b/test/test-window-utils.js
index cac94bea3..c93b0d46e 100644
--- a/test/test-window-utils.js
+++ b/test/test-window-utils.js
@@ -236,6 +236,9 @@ exports['test window watcher without untracker'] = function(assert, done) {
 };
 
 exports['test active window'] = function(assert, done) {
+  let testRunnerWindow = Cc["@mozilla.org/appshell/window-mediator;1"]
+                         .getService(Ci.nsIWindowMediator)
+                         .getMostRecentWindow("test:runner");
   let browserWindow =  Cc["@mozilla.org/appshell/window-mediator;1"]
                       .getService(Ci.nsIWindowMediator)
                       .getMostRecentWindow("navigator:browser");
@@ -252,21 +255,26 @@ exports['test active window'] = function(assert, done) {
     function() {
       assert.equal(windowUtils.activeWindow, browserWindow,
                        "Correct active window [1]");
-      nextTest();
+      continueAfterFocus(windowUtils.activeWindow = testRunnerWindow);
     },
     function() {
+      assert.equal(windowUtils.activeWindow, testRunnerWindow,
+                       "Correct active window [2]");
       assert.equal(windowUtils.activeBrowserWindow, browserWindow,
-                       "Correct active browser window [2]");
+                       "Correct active browser window [3]");
       continueAfterFocus(windowUtils.activeWindow = browserWindow);
     },
     function() {
       assert.equal(windowUtils.activeWindow, browserWindow,
-                       "Correct active window [3]");
-      nextTest();
+                       "Correct active window [4]");
+      continueAfterFocus(windowUtils.activeWindow = testRunnerWindow);
     },
     function() {
+      assert.equal(windowUtils.activeWindow, testRunnerWindow,
+                       "Correct active window [5]");
       assert.equal(windowUtils.activeBrowserWindow, browserWindow,
-                       "Correct active browser window [4]");
+                       "Correct active browser window [6]");
+      testRunnerWindow = null;
       browserWindow = null;
       done();
     }
@@ -280,6 +288,7 @@ exports['test active window'] = function(assert, done) {
   }
 
   function continueAfterFocus(targetWindow) {
+
     // Based on SimpleTest.waitForFocus
     var fm = Cc["@mozilla.org/focus-manager;1"].
              getService(Ci.nsIFocusManager);
diff --git a/test/windows/test-firefox-windows.js b/test/windows/test-firefox-windows.js
index 2b5688b5d..a0cd4f94a 100644
--- a/test/windows/test-firefox-windows.js
+++ b/test/windows/test-firefox-windows.js
@@ -10,6 +10,8 @@ const wm = Cc['@mozilla.org/appshell/window-mediator;1'].
            getService(Ci.nsIWindowMediator);
 let browserWindows;
 
+function getTestRunnerWindow() wm.getMostRecentWindow("test:runner");
+
 // TEST: open & close window
 exports.testOpenAndCloseWindow = function(test) {
   test.waitUntilDone();
@@ -178,7 +180,7 @@ exports.testActiveWindow = function(test) {
   let window2, window3;
 
   // Raw window objects
-  let rawWindow2, rawWindow3;
+  let nonBrowserWindow = getTestRunnerWindow(), rawWindow2, rawWindow3;
 
   test.waitUntilDone();
 
@@ -194,7 +196,8 @@ exports.testActiveWindow = function(test) {
       continueAfterFocus(rawWindow2);
     },
     function() {
-      nextStep();
+      nonBrowserWindow.focus();
+      continueAfterFocus(nonBrowserWindow);
     },
     function() {
       /**
@@ -220,6 +223,7 @@ exports.testActiveWindow = function(test) {
     },
     function() {
       test.assertEqual(windows.activeWindow.title, window3.title, "Correct active window - 3");
+      nonBrowserWindow.focus();
       finishTest();
     }
   ];
@@ -249,6 +253,7 @@ exports.testActiveWindow = function(test) {
   }
 
   function continueAfterFocus(targetWindow) {
+
     // Based on SimpleTest.waitForFocus
     var fm = Cc["@mozilla.org/focus-manager;1"].
              getService(Ci.nsIFocusManager);
@@ -331,12 +336,13 @@ exports.testTrackWindows = function(test) {
 
   browserWindows.on("activate", function (window) {
     let index = windows.indexOf(window);
+
     actions.push("global activate " + index)
   })
 
   browserWindows.on("deactivate", function (window) {
     let index = windows.indexOf(window);
-    if (index < 0) return;
+
     actions.push("global deactivate " + index)
   })