diff -r 000000000000 -r 6474c204b198 browser/base/content/test/general/browser_middleMouse_inherit.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/base/content/test/general/browser_middleMouse_inherit.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,55 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const middleMousePastePref = "middlemouse.contentLoadURL";
+const autoScrollPref = "general.autoScroll";
+function test() {
+  waitForExplicitFinish();
+
+  Services.prefs.setBoolPref(middleMousePastePref, true);
+  Services.prefs.setBoolPref(autoScrollPref, false);
+  let tab = gBrowser.selectedTab = gBrowser.addTab();
+
+  registerCleanupFunction(function () {
+    Services.prefs.clearUserPref(middleMousePastePref);
+    Services.prefs.clearUserPref(autoScrollPref);
+    gBrowser.removeTab(tab);
+  });
+
+  addPageShowListener(function () {
+    let pagePrincipal = gBrowser.contentPrincipal;
+
+    // copy javascript URI to the clipboard
+    let url = "javascript:1+1";
+    waitForClipboard(url,
+      function() {
+        Components.classes["@mozilla.org/widget/clipboardhelper;1"]
+                  .getService(Components.interfaces.nsIClipboardHelper)
+                  .copyString(url, document);
+      },
+      function () {
+        // Middle click on the content area
+        info("Middle clicking");
+        EventUtils.sendMouseEvent({type: "click", button: 1}, gBrowser);
+      },
+      function() {
+        ok(false, "Failed to copy URL to the clipboard");
+        finish();
+      }
+    );
+
+    addPageShowListener(function () {
+      is(gBrowser.currentURI.spec, url, "url loaded by middle click");
+      ok(!gBrowser.contentPrincipal.equals(pagePrincipal),
+         "middle click load of " + url + " should produce a page with a different principal");
+      finish();
+    });
+  });
+}
+
+function addPageShowListener(func) {
+  gBrowser.selectedBrowser.addEventListener("pageshow", function loadListener() {
+    gBrowser.selectedBrowser.removeEventListener("pageshow", loadListener, false);
+    func();
+  });
+}