diff --git a/widget/public/nsIDMWidget.h b/widget/public/nsIDMWidget.h
new file mode 100644
index 000000000000..79d0d1541827
--- /dev/null
+++ b/widget/public/nsIDMWidget.h
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * The contents of this file are subject to the Netscape Public License
+ * Version 1.0 (the "NPL"); you may not use this file except in
+ * compliance with the NPL.  You may obtain a copy of the NPL at
+ * http://www.mozilla.org/NPL/
+ *
+ * Software distributed under the NPL is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
+ * for the specific language governing rights and limitations under the
+ * NPL.
+ *
+ * The Initial Developer of this code under the NPL is Netscape
+ * Communications Corporation.  Portions created by Netscape are
+ * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
+ * Reserved.
+ */
+
+#ifndef nsIDMWidget_h___
+#define nsIDMWidget_h___
+
+#include "nsISupports.h"
+#include "nsGUIEvent.h"
+
+class nsIDataModel;
+
+// {E6ED4EC4-5985-11d2-96ED-00104B7B7DEB}
+#define NS_IDATAMODEL_IID      \
+{ 0xe6ed4ec4, 0x5985, 0x11d2, \
+	{ 0x96, 0xed, 0x0, 0x10, 0x4b, 0x7b, 0x7d, 0xeb } }
+
+// Events that the widget can receive from the data model.
+const cDSImageLoaded = 0;
+
+class nsIDMWidget : public nsISupports
+{
+
+public:
+	// Inspectors
+	NS_IMETHOD GetDataModel(nsIDataModel*& pDataModel) = 0;
+
+	// Setters
+	NS_IMETHOD SetDataModel(nsIDataModel* pDataModel) = 0;
+
+	NS_IMETHOD HandleDataModelEvent(int aEvent, nsIDMItem* pNode) = 0;
+};
+
+#endif /* nsIDMWidget_h___ */
+