diff --git a/xpfe/appshell/src/nsContentTreeOwner.cpp b/xpfe/appshell/src/nsContentTreeOwner.cpp
index 2e1430165179..76937d6638a5 100644
--- a/xpfe/appshell/src/nsContentTreeOwner.cpp
+++ b/xpfe/appshell/src/nsContentTreeOwner.cpp
@@ -40,7 +40,8 @@ static NS_DEFINE_CID(kWindowMediatorCID, NS_WINDOWMEDIATOR_CID);
 //***    nsContentTreeOwner: Object Management
 //*****************************************************************************
 
-nsContentTreeOwner::nsContentTreeOwner() : mXULWindow(nsnull)
+nsContentTreeOwner::nsContentTreeOwner(PRBool fPrimary) : mXULWindow(nsnull), 
+   mPrimary(fPrimary)
 {
 	NS_INIT_REFCNT();
 }
@@ -306,6 +307,10 @@ NS_IMETHODIMP nsContentTreeOwner::GetTitle(PRUnichar** aTitle)
 
 NS_IMETHODIMP nsContentTreeOwner::SetTitle(const PRUnichar* aTitle)
 {
+   // We only allow the title to be set from the primary content shell
+   if(!mPrimary)
+      return NS_OK;
+
    // Get the window title modifiers
    nsCOMPtr<nsIDOMElement> docShellElement;
    mXULWindow->GetDOMElementFromDocShell(mXULWindow->mDocShell, 
diff --git a/xpfe/appshell/src/nsContentTreeOwner.h b/xpfe/appshell/src/nsContentTreeOwner.h
index b445d1aa9995..80f498123ed4 100644
--- a/xpfe/appshell/src/nsContentTreeOwner.h
+++ b/xpfe/appshell/src/nsContentTreeOwner.h
@@ -41,7 +41,7 @@ public:
    NS_DECL_NSIDOCSHELLTREEOWNER
 
 protected:
-   nsContentTreeOwner();
+   nsContentTreeOwner(PRBool fPrimary);
    virtual ~nsContentTreeOwner();
 
    void XULWindow(nsXULWindow* aXULWindow);
@@ -49,6 +49,7 @@ protected:
 
 protected:
    nsXULWindow*      mXULWindow;
+   PRBool            mPrimary;
 };
 
 #endif /* nsContentTreeOwner_h__ */
diff --git a/xpfe/appshell/src/nsXULWindow.cpp b/xpfe/appshell/src/nsXULWindow.cpp
index ce4229b7a053..39fdff374990 100644
--- a/xpfe/appshell/src/nsXULWindow.cpp
+++ b/xpfe/appshell/src/nsXULWindow.cpp
@@ -46,8 +46,9 @@ static NS_DEFINE_CID(kWindowMediatorCID, NS_WINDOWMEDIATOR_CID);
 //***    nsXULWindow: Object Management
 //*****************************************************************************
 
-nsXULWindow::nsXULWindow() : mContentTreeOwner(nsnull), 
-   mChromeTreeOwner(nsnull)
+nsXULWindow::nsXULWindow() : mChromeTreeOwner(nsnull), 
+   mContentTreeOwner(nsnull), mPrimaryContentTreeOwner(nsnull) 
+   
 {
 	NS_INIT_REFCNT();
 }
@@ -260,6 +261,11 @@ NS_IMETHODIMP nsXULWindow::Destroy()
       mContentTreeOwner->XULWindow(nsnull);
       NS_RELEASE(mContentTreeOwner);
       }
+   if(mPrimaryContentTreeOwner)
+      {
+      mPrimaryContentTreeOwner->XULWindow(nsnull);
+      NS_RELEASE(mPrimaryContentTreeOwner);
+      }
    if(mChromeTreeOwner)
       {
       mChromeTreeOwner->XULWindow(nsnull);
@@ -461,7 +467,7 @@ NS_IMETHODIMP nsXULWindow::EnsureContentTreeOwner()
    if(mContentTreeOwner)
       return NS_OK;
 
-   mContentTreeOwner = new nsContentTreeOwner();
+   mContentTreeOwner = new nsContentTreeOwner(PR_FALSE);
    NS_ENSURE_TRUE(mContentTreeOwner, NS_ERROR_FAILURE);
 
    NS_ADDREF(mContentTreeOwner);
@@ -470,6 +476,20 @@ NS_IMETHODIMP nsXULWindow::EnsureContentTreeOwner()
    return NS_OK;
 }
 
+NS_IMETHODIMP nsXULWindow::EnsurePrimaryContentTreeOwner()
+{
+   if(mPrimaryContentTreeOwner)
+      return NS_OK;
+
+   mPrimaryContentTreeOwner = new nsContentTreeOwner(PR_TRUE);
+   NS_ENSURE_TRUE(mPrimaryContentTreeOwner, NS_ERROR_FAILURE);
+
+   NS_ADDREF(mPrimaryContentTreeOwner);
+   mPrimaryContentTreeOwner->XULWindow(this);
+
+   return NS_OK;
+}
+
 NS_IMETHODIMP nsXULWindow::GetDOMElementFromDocShell(nsIDocShell* aDocShell,
    nsIDOMElement** aDOMElement)
 {
@@ -572,8 +592,16 @@ NS_IMETHODIMP nsXULWindow::ContentShellAdded(nsIDocShellTreeItem* aContentShell,
 
    if(!treeOwner)
       {
-      NS_ENSURE_SUCCESS(EnsureContentTreeOwner(), NS_ERROR_FAILURE);
-      aContentShell->SetTreeOwner(mContentTreeOwner);
+      if(aPrimary)
+         {
+         NS_ENSURE_SUCCESS(EnsurePrimaryContentTreeOwner(), NS_ERROR_FAILURE);
+         aContentShell->SetTreeOwner(mPrimaryContentTreeOwner);
+         }
+      else
+         {
+         NS_ENSURE_SUCCESS(EnsureContentTreeOwner(), NS_ERROR_FAILURE);
+         aContentShell->SetTreeOwner(mContentTreeOwner);
+         }
       }
 
    return NS_OK;
diff --git a/xpfe/appshell/src/nsXULWindow.h b/xpfe/appshell/src/nsXULWindow.h
index 82c745c0404b..9814fd345214 100644
--- a/xpfe/appshell/src/nsXULWindow.h
+++ b/xpfe/appshell/src/nsXULWindow.h
@@ -58,6 +58,7 @@ protected:
 
    NS_IMETHOD EnsureChromeTreeOwner();
    NS_IMETHOD EnsureContentTreeOwner();
+   NS_IMETHOD EnsurePrimaryContentTreeOwner();
 
    NS_IMETHOD GetDOMElementFromDocShell(nsIDocShell* aDocShell, 
       nsIDOMElement** aDOMElement);
@@ -68,6 +69,7 @@ protected:
 protected:
    nsChromeTreeOwner*      mChromeTreeOwner;
    nsContentTreeOwner*     mContentTreeOwner;
+   nsContentTreeOwner*     mPrimaryContentTreeOwner;
    nsCOMPtr<nsIWidget>     mWindow;
    nsCOMPtr<nsIDocShell>   mDocShell;
    nsVoidArray             mContentShells;