diff -r 000000000000 -r 6474c204b198 browser/base/content/test/general/browser_bug575830.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/base/content/test/general/browser_bug575830.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,33 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+"use strict";
+
+function test() {
+  let tab1, tab2;
+  const TEST_IMAGE = "http://example.org/browser/browser/base/content/test/general/moz.png";
+
+  waitForExplicitFinish();
+
+  Task.spawn(function () {
+    tab1 = gBrowser.addTab();
+    tab2 = gBrowser.addTab();
+    yield FullZoomHelper.selectTabAndWaitForLocationChange(tab1);
+    yield FullZoomHelper.load(tab1, TEST_IMAGE);
+
+    is(ZoomManager.zoom, 1, "initial zoom level for first should be 1");
+
+    FullZoom.enlarge();
+    let zoom = ZoomManager.zoom;
+    isnot(zoom, 1, "zoom level should have changed");
+
+    yield FullZoomHelper.selectTabAndWaitForLocationChange(tab2);
+    is(ZoomManager.zoom, 1, "initial zoom level for second tab should be 1");
+
+    yield FullZoomHelper.selectTabAndWaitForLocationChange(tab1);
+    is(ZoomManager.zoom, zoom, "zoom level for first tab should not have changed");
+
+    yield FullZoomHelper.removeTabAndWaitForLocationChange(tab1);
+    yield FullZoomHelper.removeTabAndWaitForLocationChange(tab2);
+  }).then(finish, FullZoomHelper.failAndContinue(finish));
+}