diff --git a/widget/public/nsIWidget.h b/widget/public/nsIWidget.h
index fb14c4d96c68..305dea03526d 100644
--- a/widget/public/nsIWidget.h
+++ b/widget/public/nsIWidget.h
@@ -373,7 +373,16 @@ class nsIWidget : public nsISupports {
 
     NS_IMETHOD Invalidate(PRBool aIsSynchronous) = 0;
 
-  
+    /**
+     * Invalidate a specified rect for a widget and repaints it.
+     *
+     * @param aIsSynchronouse PR_TRUE then repaint synchronously. If PR_FALSE repaint later.
+     *
+     */
+
+    NS_IMETHOD Invalidate(const nsRect & aRect, PRBool aIsSynchronous) = 0;
+
+
     /**
      * Adds a mouse listener to this widget
      * Any existing mouse listener is replaced
diff --git a/widget/src/windows/nsWindow.cpp b/widget/src/windows/nsWindow.cpp
index 3cccdc808045..016b80c7c7aa 100644
--- a/widget/src/windows/nsWindow.cpp
+++ b/widget/src/windows/nsWindow.cpp
@@ -1028,6 +1028,29 @@ NS_METHOD nsWindow::Invalidate(PRBool aIsSynchronous)
     return NS_OK;
 }
 
+//-------------------------------------------------------------------------
+//
+// Invalidate this component visible area
+//
+//-------------------------------------------------------------------------
+NS_METHOD nsWindow::Invalidate(const nsRect & aRect, PRBool aIsSynchronous)
+{
+  RECT rect;
+
+  if (mWnd) {
+    rect.left   = aRect.x;
+    rect.top    = aRect.y;
+    rect.right  = aRect.x + aRect.width;
+    rect.bottom = aRect.y  + aRect.height;
+    VERIFY(::InvalidateRect(mWnd, &rect, TRUE));
+    if (aIsSynchronous) {
+      VERIFY(::UpdateWindow(mWnd));
+    }
+  }
+  return NS_OK;
+}
+
+
 
 //-------------------------------------------------------------------------
 //
diff --git a/widget/src/windows/nsWindow.h b/widget/src/windows/nsWindow.h
index 9b2422566df5..903d9ad9e03c 100644
--- a/widget/src/windows/nsWindow.h
+++ b/widget/src/windows/nsWindow.h
@@ -103,6 +103,7 @@ public:
     NS_IMETHOD              SetFont(const nsFont &aFont);
     NS_IMETHOD              SetCursor(nsCursor aCursor);
     NS_IMETHOD              Invalidate(PRBool aIsSynchronous);
+    NS_IMETHOD              Invalidate(const nsRect & aRect, PRBool aIsSynchronous);
     virtual void*           GetNativeData(PRUint32 aDataType);
     NS_IMETHOD              SetColorMap(nsColorMap *aColorMap);
     NS_IMETHOD              Scroll(PRInt32 aDx, PRInt32 aDy, nsRect *aClipRect);