diff --git a/accessible/src/base/nsRootAccessible.cpp b/accessible/src/base/nsRootAccessible.cpp
index 355effda1b5e..a0511f38a1d1 100644
--- a/accessible/src/base/nsRootAccessible.cpp
+++ b/accessible/src/base/nsRootAccessible.cpp
@@ -574,6 +574,59 @@ nsRootAccessible::Shutdown()
   nsDocAccessibleWrap::Shutdown();
 }
 
+// nsRootAccessible protected member
+already_AddRefed<nsIDocShellTreeItem>
+nsRootAccessible::GetContentDocShell(nsIDocShellTreeItem *aStart)
+{
+  if (!aStart) {
+    return nsnull;
+  }
+
+  PRInt32 itemType;
+  aStart->GetItemType(&itemType);
+  if (itemType == nsIDocShellTreeItem::typeContent) {
+    nsDocAccessible *accDoc = nsAccUtils::GetDocAccessibleFor(aStart);
+
+    // Hidden documents don't have accessibles (like SeaMonkey's sidebar),
+    // they are of no interest for a11y.
+    if (!accDoc)
+      return nsnull;
+
+    // If ancestor chain of accessibles is not completely visible,
+    // don't use this one. This happens for example if it's inside
+    // a background tab (tabbed browsing)
+    nsAccessible* parent = accDoc->Parent();
+    while (parent) {
+      if (parent->State() & states::INVISIBLE)
+        return nsnull;
+
+      if (parent == this)
+        break; // Don't check past original root accessible we started with
+
+      parent = parent->Parent();
+    }
+
+    NS_ADDREF(aStart);
+    return aStart;
+  }
+  nsCOMPtr<nsIDocShellTreeNode> treeNode(do_QueryInterface(aStart));
+  if (treeNode) {
+    PRInt32 subDocuments;
+    treeNode->GetChildCount(&subDocuments);
+    for (PRInt32 count = 0; count < subDocuments; count ++) {
+      nsCOMPtr<nsIDocShellTreeItem> treeItemChild, contentTreeItem;
+      treeNode->GetChildAt(count, getter_AddRefs(treeItemChild));
+      NS_ENSURE_TRUE(treeItemChild, nsnull);
+      contentTreeItem = GetContentDocShell(treeItemChild);
+      if (contentTreeItem) {
+        NS_ADDREF(aStart = contentTreeItem);
+        return aStart;
+      }
+    }
+  }
+  return nsnull;
+}
+
 // nsIAccessible method
 Relation
 nsRootAccessible::RelationByType(PRUint32 aType)
@@ -581,25 +634,14 @@ nsRootAccessible::RelationByType(PRUint32 aType)
   if (!mDocument || aType != nsIAccessibleRelation::RELATION_EMBEDS)
     return nsDocAccessibleWrap::RelationByType(aType);
 
-  nsIDOMWindow* rootWindow = mDocument->GetWindow();
-  if (rootWindow) {
-    nsCOMPtr<nsIDOMWindow> contentWindow;
-    rootWindow->GetContent(getter_AddRefs(contentWindow));
-    if (contentWindow) {
-      nsCOMPtr<nsIDOMDocument> contentDOMDocument;
-      contentWindow->GetDocument(getter_AddRefs(contentDOMDocument));
-      nsCOMPtr<nsIDocument> contentDocumentNode =
-        do_QueryInterface(contentDOMDocument);
-      if (contentDocumentNode) {
-        nsDocAccessible* contentDocument =
-          GetAccService()->GetDocAccessible(contentDocumentNode);
-        if (contentDocument)
-          return Relation(contentDocument);
-      }
-    }
-  }
+  nsCOMPtr<nsIDocShellTreeItem> treeItem =
+    nsCoreUtils::GetDocShellTreeItemFor(mDocument);
+  nsCOMPtr<nsIDocShellTreeItem> contentTreeItem = GetContentDocShell(treeItem);
+  // there may be no content area, so we need a null check
+  if (!contentTreeItem)
+    return Relation();
 
-  return Relation();
+  return Relation(nsAccUtils::GetDocAccessibleFor(contentTreeItem));
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/accessible/src/base/nsRootAccessible.h b/accessible/src/base/nsRootAccessible.h
index b7f02ffddbca..6feb79a91005 100644
--- a/accessible/src/base/nsRootAccessible.h
+++ b/accessible/src/base/nsRootAccessible.h
@@ -127,7 +127,8 @@ protected:
 
     PRUint32 GetChromeFlags();
 #endif
-
+    already_AddRefed<nsIDocShellTreeItem>
+           GetContentDocShell(nsIDocShellTreeItem *aStart);
     nsRefPtr<nsCaretAccessible> mCaretAccessible;
 };
 
diff --git a/accessible/tests/mochitest/relations/Makefile.in b/accessible/tests/mochitest/relations/Makefile.in
index 5fc8bf6d8789..5a7654412d37 100644
--- a/accessible/tests/mochitest/relations/Makefile.in
+++ b/accessible/tests/mochitest/relations/Makefile.in
@@ -48,7 +48,6 @@ include $(topsrcdir)/config/rules.mk
 # test_tabbrowser.xul disabled for misusing <tabbrowser> (bug 715857)
 
 _TEST_FILES =\
-		test_embeds.xul \
 		test_general.html \
 		test_general.xul \
 		test_tree.xul \
diff --git a/accessible/tests/mochitest/relations/test_embeds.xul b/accessible/tests/mochitest/relations/test_embeds.xul
deleted file mode 100644
index 5d0ddcfa9990..000000000000
--- a/accessible/tests/mochitest/relations/test_embeds.xul
+++ /dev/null
@@ -1,152 +0,0 @@
-<?xml version="1.0"?>
-<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
-<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
-                 type="text/css"?>
-
-<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
-        title="Embeds relation tests">
-
-  <script type="application/javascript"
-          src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
-  <script type="application/javascript"
-          src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"></script>
-
-  <script type="application/javascript"
-          src="../common.js"></script>
-  <script type="application/javascript"
-          src="../role.js"></script>
-  <script type="application/javascript"
-          src="../states.js"></script>
-  <script type="application/javascript"
-          src="../events.js"></script>
-  <script type="application/javascript"
-          src="../relations.js"></script>
-
-  <script type="application/javascript">
-  <![CDATA[
-    ////////////////////////////////////////////////////////////////////////////
-    // Helpers
-
-    function tabBrowser()
-    {
-      return gBrowserWnd.gBrowser;
-    }
-
-    function currentBrowser()
-    {
-      return tabBrowser().selectedBrowser;
-    }
-
-    function currentTabDocument()
-    {
-      return currentBrowser().contentDocument;
-    }
-
-    ////////////////////////////////////////////////////////////////////////////
-    // Invokers
-
-    function loadURI(aURI)
-    {
-      this.invoke = function loadURI_invoke()
-      {
-        tabBrowser().loadURI(aURI);
-      }
-
-      this.eventSeq = [
-        new invokerChecker(EVENT_REORDER, currentBrowser)
-      ];
-
-      this.finalCheck = function loadURI_finalCheck()
-      {
-        testRelation(gBrowserWnd.document, RELATION_EMBEDS,
-                     getAccessible(currentTabDocument()));
-      }
-
-      this.getID = function loadURI_getID()
-      {
-        return "load uri " + aURI;
-      }
-    }
-
-    function loadOneTab(aURI)
-    {
-      this.invoke = function loadOneTab_invoke()
-      {
-        tabBrowser().loadOneTab(aURI, null, null, null, false);
-      }
-
-      this.eventSeq = [
-        new invokerChecker(EVENT_REORDER, currentBrowser)
-      ];
-
-      this.finalCheck = function loadURI_finalCheck()
-      {
-        testRelation(gBrowserWnd.document, RELATION_EMBEDS,
-                     getAccessible(currentTabDocument()));
-      }
-
-      this.getID = function loadOneTab_getID()
-      {
-        return "load uri '" + aURI + "' in new tab";
-      }
-    }
-
-    ////////////////////////////////////////////////////////////////////////////
-    // Testing
-
-    var gBrowserWnd = null;
-    function loadBrowser()
-    {
-      gBrowserWnd = window.openDialog("chrome://browser/content/", "_blank",
-                                      "chrome,all,dialog=no", "about:");
-
-      addA11yLoadEvent(startTests, gBrowserWnd);
-    }
-
-    function startTests()
-    {
-      // Wait for tab load.
-      var browser = currentBrowser();
-      addA11yLoadEvent(doTests, browser.contentWindow);
-    }
-
-    //gA11yEventDumpToConsole = true; // debug
-
-    var gQueue = null;
-    function doTests()
-    {
-      testRelation(gBrowserWnd.document, RELATION_EMBEDS,
-                   getAccessible(currentTabDocument()));
-
-      gQueue = new eventQueue();
-
-      gQueue.push(new loadURI("about:about"));
-      gQueue.push(new loadOneTab("about:mozilla"));
-
-      gQueue.onFinish = function()
-      {
-        gBrowserWnd.close();
-      }
-      gQueue.invoke();
-    }
-
-    SimpleTest.waitForExplicitFinish();
-    addLoadEvent(loadBrowser);
-  ]]>
-  </script>
-
-  <vbox flex="1" style="overflow: auto;">
-  <body xmlns="http://www.w3.org/1999/xhtml">
-    <a target="_blank"
-       href="https://bugzilla.mozilla.org/show_bug.cgi?id=707654"
-       title="Embeds relation on root accessible can return not content document">
-      Mozilla Bug 707654
-    </a>
-    <p id="display"></p>
-    <div id="content" style="display: none">
-    </div>
-    <pre id="test">
-    </pre>
-  </body>
-  </vbox>
-</window>
diff --git a/accessible/tests/mochitest/relations/test_general.html b/accessible/tests/mochitest/relations/test_general.html
index d487f349ade2..71bf6f8600d2 100644
--- a/accessible/tests/mochitest/relations/test_general.html
+++ b/accessible/tests/mochitest/relations/test_general.html
@@ -126,6 +126,19 @@
       testRelation("legend", RELATION_LABEL_FOR, "fieldset");
       testRelation("fieldset", RELATION_LABELLED_BY, "legend");
 
+      // 'embeds' relation for root accessible
+      var docAcc = null;
+      var parentOfDocAcc = null;
+      var parentDocAcc = getAccessible(document);
+      do {
+        docAcc = parentDocAcc;
+        parentOfDocAcc = getAccessible(docAcc.parent, [nsIAccessNode]);
+        parentDocAcc = getAccessible(parentOfDocAcc.document,
+                                     [nsIAccessible]);
+      } while (getRole(parentDocAcc) != ROLE_CHROME_WINDOW)
+
+      testRelation(parentDocAcc, RELATION_EMBEDS, docAcc);
+
       // finish test
       SimpleTest.finish();
     }
diff --git a/accessible/tests/mochitest/relations/test_general.xul b/accessible/tests/mochitest/relations/test_general.xul
index 23bf7276b28b..ca288d1bf6c1 100644
--- a/accessible/tests/mochitest/relations/test_general.xul
+++ b/accessible/tests/mochitest/relations/test_general.xul
@@ -103,6 +103,19 @@
       // 'default button' relation
       testRelation("textbox", RELATION_DEFAULT_BUTTON, "submit");
 
+      // 'embeds' relation for root accessible
+      var docAcc = null;
+      var parentOfDocAcc = null;
+      var parentDocAcc = getAccessible(document);
+      do {
+        docAcc = parentDocAcc;
+        parentOfDocAcc = getAccessible(docAcc.parent, [nsIAccessNode]);
+        parentDocAcc = getAccessible(parentOfDocAcc.document,
+                                     [nsIAccessible]);
+      } while (getRole(parentDocAcc) != ROLE_CHROME_WINDOW)
+
+      testRelation(parentDocAcc, RELATION_EMBEDS, docAcc);
+
       // 'labelled by'/'label for' relation for xul:goupbox and xul:label of
       // xul:caption
       var groupboxAcc = getAccessible("groupbox");