diff --git a/browser/components/extensions/ext-windows.js b/browser/components/extensions/ext-windows.js
index f83bc4b8194..9c878827622 100644
--- a/browser/components/extensions/ext-windows.js
+++ b/browser/components/extensions/ext-windows.js
@@ -60,7 +60,7 @@ extensions.registerAPI((extension, context) => {
         runSafe(context, callback, WindowManager.convert(extension, window, getInfo));
       },
 
-      getAll: function(getAll, callback) {
+      getAll: function(getInfo, callback) {
         let e = Services.wm.getEnumerator("navigator:browser");
         let windows = [];
         while (e.hasMoreElements()) {
@@ -131,7 +131,10 @@ extensions.registerAPI((extension, context) => {
           Services.focus.activeWindow = window;
         }
         // TODO: All the other properties...
-        runSafe(context, callback, WindowManager.convert(extension, window));
+
+        if (callback) {
+          runSafe(context, callback, WindowManager.convert(extension, window));
+        }
       },
 
       remove: function(windowId, callback) {
diff --git a/browser/components/extensions/test/browser/browser.ini b/browser/components/extensions/test/browser/browser.ini
index 2ce3ab84db0..a64633ab2d1 100644
--- a/browser/components/extensions/test/browser/browser.ini
+++ b/browser/components/extensions/test/browser/browser.ini
@@ -6,3 +6,4 @@ skip-if = os == 'android' || buildapp == 'b2g' || os == 'mac'
 [browser_ext_tabs_executeScript.js]
 [browser_ext_tabs_query.js]
 [browser_ext_tabs_update.js]
+[browser_ext_windows_update.js]
diff --git a/browser/components/extensions/test/browser/browser_ext_windows_update.js b/browser/components/extensions/test/browser/browser_ext_windows_update.js
new file mode 100644
index 00000000000..eb70e2c3356
--- /dev/null
+++ b/browser/components/extensions/test/browser/browser_ext_windows_update.js
@@ -0,0 +1,51 @@
+add_task(function* () {
+  function promiseWaitForFocus(aWindow) {
+    return new Promise(function(aResolve, aReject) {
+      waitForFocus(function() {
+        ok(Services.focus.activeWindow === aWindow, "correct window focused");
+        aResolve();
+      }, aWindow);
+    });
+  }
+
+  let window1 = window;
+  let window2 = yield BrowserTestUtils.openNewBrowserWindow();
+
+  Services.focus.activeWindow = window2;
+  yield promiseWaitForFocus(window2);
+
+  let extension = ExtensionTestUtils.loadExtension({
+    manifest: {
+      "permissions": ["windows"]
+    },
+
+    background: function() {
+      browser.windows.getAll(undefined, function(wins) {
+        browser.test.assertEq(wins.length, 2, "should have two windows");
+
+        // Sort the unfocused window to the lower index.
+        wins.sort(function(win1, win2) {
+          if (win1.focused === win2.focused) {
+            return 0;
+          }
+
+          return win1.focused ? 1 : -1;
+        });
+
+        browser.windows.update(wins[0].id, {focused: true}, function() {
+          browser.test.sendMessage("check");
+        });
+
+      });
+    },
+  });
+
+  yield extension.startup();
+  yield extension.awaitMessage("check");
+
+  yield promiseWaitForFocus(window1);
+
+  yield extension.unload();
+
+  yield BrowserTestUtils.closeWindow(window2);
+});
\ No newline at end of file