diff -r 000000000000 -r 6474c204b198 browser/devtools/scratchpad/test/browser_scratchpad_tab_switch.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/scratchpad/test/browser_scratchpad_tab_switch.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,103 @@
+/* vim: set ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+let tab1;
+let tab2;
+let sp;
+
+function test()
+{
+  waitForExplicitFinish();
+
+  tab1 = gBrowser.addTab();
+  gBrowser.selectedTab = tab1;
+  gBrowser.selectedBrowser.addEventListener("load", function onLoad1() {
+    gBrowser.selectedBrowser.removeEventListener("load", onLoad1, true);
+
+    tab2 = gBrowser.addTab();
+    gBrowser.selectedTab = tab2;
+    gBrowser.selectedBrowser.addEventListener("load", function onLoad2() {
+      gBrowser.selectedBrowser.removeEventListener("load", onLoad2, true);
+      openScratchpad(runTests);
+    }, true);
+    content.location = "data:text/html,test context switch in Scratchpad tab 2";
+  }, true);
+
+  content.location = "data:text/html,test context switch in Scratchpad tab 1";
+}
+
+function runTests()
+{
+  sp = gScratchpadWindow.Scratchpad;
+
+  let contentMenu = gScratchpadWindow.document.getElementById("sp-menu-content");
+  let browserMenu = gScratchpadWindow.document.getElementById("sp-menu-browser");
+  let notificationBox = sp.notificationBox;
+
+  ok(contentMenu, "found #sp-menu-content");
+  ok(browserMenu, "found #sp-menu-browser");
+  ok(notificationBox, "found Scratchpad.notificationBox");
+
+  sp.setContentContext();
+
+  is(sp.executionContext, gScratchpadWindow.SCRATCHPAD_CONTEXT_CONTENT,
+     "executionContext is content");
+
+  is(contentMenu.getAttribute("checked"), "true",
+     "content menuitem is checked");
+
+  isnot(browserMenu.getAttribute("checked"), "true",
+     "chrome menuitem is not checked");
+
+  is(notificationBox.currentNotification, null,
+     "there is no notification currently shown for content context");
+
+  sp.setText("window.foosbug653108 = 'aloha';");
+
+  ok(!content.wrappedJSObject.foosbug653108,
+     "no content.foosbug653108");
+
+  sp.run().then(function() {
+    is(content.wrappedJSObject.foosbug653108, "aloha",
+       "content.foosbug653108 has been set");
+
+    gBrowser.tabContainer.addEventListener("TabSelect", runTests2, true);
+    gBrowser.selectedTab = tab1;
+  });
+}
+
+function runTests2() {
+  gBrowser.tabContainer.removeEventListener("TabSelect", runTests2, true);
+
+  ok(!window.foosbug653108, "no window.foosbug653108");
+
+  sp.setText("window.foosbug653108");
+  sp.run().then(function([, , result]) {
+    isnot(result, "aloha", "window.foosbug653108 is not aloha");
+
+    sp.setText("window.foosbug653108 = 'ahoyhoy';");
+    sp.run().then(function() {
+      is(content.wrappedJSObject.foosbug653108, "ahoyhoy",
+         "content.foosbug653108 has been set 2");
+
+      gBrowser.selectedBrowser.addEventListener("load", runTests3, true);
+      content.location = "data:text/html,test context switch in Scratchpad location 2";
+    });
+  });
+}
+
+function runTests3() {
+  gBrowser.selectedBrowser.removeEventListener("load", runTests3, true);
+  // Check that the sandbox is not cached.
+
+  sp.setText("typeof foosbug653108;");
+  sp.run().then(function([, , result]) {
+    is(result, "undefined", "global variable does not exist");
+
+    tab1 = null;
+    tab2 = null;
+    sp = null;
+    finish();
+  });
+}