diff --git a/mozilla/docshell/base/nsIDocShellTreeOwner.idl b/mozilla/docshell/base/nsIDocShellTreeOwner.idl
index 0982ac782ba..9b251dd33f0 100644
--- a/mozilla/docshell/base/nsIDocShellTreeOwner.idl
+++ b/mozilla/docshell/base/nsIDocShellTreeOwner.idl
@@ -71,12 +71,18 @@ interface nsIDocShellTreeOwner : nsISupports
 	*/
 	void showModal();	
     
-    /*
-    Exit a modal loop if we're in one
-    @param aStatus - the result code to return from showModal
-     */
-    void exitModalLoop(in nsresult aStatus);
-      
+	/**
+	Is the window modal (that is, currently executing a modal loop)?
+        @return true if it's a modal window
+	*/
+	boolean isModal();
+
+	/**
+	Exit a modal loop if we're in one
+	@param aStatus - the result code to return from showModal
+	*/
+	void exitModalLoop(in nsresult aStatus);
+
 	/*
 	Tells the implementer of this interface to create a new window.  This is
 	a new logical window.  Meaning in some implementations the result may not
diff --git a/mozilla/embedding/browser/webBrowser/nsDocShellTreeOwner.cpp b/mozilla/embedding/browser/webBrowser/nsDocShellTreeOwner.cpp
index 533ba3c824b..3df3b1a3254 100644
--- a/mozilla/embedding/browser/webBrowser/nsDocShellTreeOwner.cpp
+++ b/mozilla/embedding/browser/webBrowser/nsDocShellTreeOwner.cpp
@@ -250,6 +250,14 @@ NS_IMETHODIMP nsDocShellTreeOwner::ShowModal()
    return mWebBrowserChrome->ShowAsModal();
 }
 
+NS_IMETHODIMP nsDocShellTreeOwner::IsModal(PRBool *_retval)
+{
+   if(mTreeOwner)
+      return mTreeOwner->IsModal(_retval);
+
+   return mWebBrowserChrome->IsWindowModal(_retval);
+}
+
 NS_IMETHODIMP nsDocShellTreeOwner::ExitModalLoop(nsresult aStatus)
 {
    if(mTreeOwner)
diff --git a/mozilla/embedding/browser/webBrowser/nsIWebBrowserChrome.idl b/mozilla/embedding/browser/webBrowser/nsIWebBrowserChrome.idl
index 7858870e918..c2987f348af 100644
--- a/mozilla/embedding/browser/webBrowser/nsIWebBrowserChrome.idl
+++ b/mozilla/embedding/browser/webBrowser/nsIWebBrowserChrome.idl
@@ -124,12 +124,18 @@ interface nsIWebBrowserChrome : nsISupports
 	*/
 	void showAsModal();
 
-    /**
-        Exit a modal event loop if we're in one. The implementation
-        should also exit out of the loop if the window is destroyed.
-        @param aStatus - the result code to return from showAsModal
-    */
-    void exitModalEventLoop(in nsresult aStatus);
+	/**
+	Is the window modal (that is, currently executing a modal loop)?
+        @return true if it's a modal window
+	*/
+	boolean isWindowModal();
+
+	/**
+	 Exit a modal event loop if we're in one. The implementation
+	 should also exit out of the loop if the window is destroyed.
+	 @param aStatus - the result code to return from showAsModal
+	*/
+	void exitModalEventLoop(in nsresult aStatus);
 
 	/*
 	Sets the persistence of different dimensions of the window.
diff --git a/mozilla/xpfe/appshell/src/nsChromeTreeOwner.cpp b/mozilla/xpfe/appshell/src/nsChromeTreeOwner.cpp
index e58ddd13f92..48490edcc9f 100644
--- a/mozilla/xpfe/appshell/src/nsChromeTreeOwner.cpp
+++ b/mozilla/xpfe/appshell/src/nsChromeTreeOwner.cpp
@@ -181,6 +181,12 @@ NS_IMETHODIMP nsChromeTreeOwner::ShowModal()
    return mXULWindow->ShowModal();   
 }
 
+NS_IMETHODIMP nsChromeTreeOwner::IsModal(PRBool *_retval)
+{
+  *_retval = mXULWindow->mContinueModalLoop;
+  return NS_OK;
+}
+
 NS_IMETHODIMP nsChromeTreeOwner::ExitModalLoop(nsresult aStatus)
 {
    return mXULWindow->ExitModalLoop(aStatus);   
diff --git a/mozilla/xpfe/appshell/src/nsContentTreeOwner.cpp b/mozilla/xpfe/appshell/src/nsContentTreeOwner.cpp
index b91e3e55cc0..9bbb8985cff 100644
--- a/mozilla/xpfe/appshell/src/nsContentTreeOwner.cpp
+++ b/mozilla/xpfe/appshell/src/nsContentTreeOwner.cpp
@@ -183,6 +183,12 @@ NS_IMETHODIMP nsContentTreeOwner::ShowModal()
    return mXULWindow->ShowModal();   
 }
 
+NS_IMETHODIMP nsContentTreeOwner::IsModal(PRBool *_retval)
+{
+  *_retval = mXULWindow->mContinueModalLoop;
+  return NS_OK;
+}
+
 NS_IMETHODIMP nsContentTreeOwner::ExitModalLoop(nsresult aStatus)
 {
    return mXULWindow->ExitModalLoop(aStatus);   
@@ -283,6 +289,11 @@ NS_IMETHODIMP nsContentTreeOwner::ShowAsModal()
    return ShowModal();
 }
 
+NS_IMETHODIMP nsContentTreeOwner::IsWindowModal(PRBool *_retval)
+{
+  return IsModal(_retval);
+}
+
 NS_IMETHODIMP nsContentTreeOwner::ExitModalEventLoop(nsresult aStatus)
 {
    return ExitModalLoop(aStatus);