/// <summary>
        /// Occurs when this command is clicked
        /// </summary>
        public override void OnClick()
        {
            //launch a new OpenFile dialog
            OpenFileDialog dlg = new OpenFileDialog();

            dlg.Filter      = "Map Documents (*.mxd)|*.mxd";
            dlg.Multiselect = false;
            dlg.Title       = "Open Map Document";
            if (dlg.ShowDialog() == DialogResult.OK)
            {
                string docName = dlg.FileName;

                IMapDocument pMapDoc = new MapDocumentClass();

                if (pMapDoc.get_IsPresent(docName) && !pMapDoc.get_IsPasswordProtected(docName))
                {
                    pMapDoc.Open(docName, string.Empty);

                    // set the first map as the active view
                    IMap map = pMapDoc.get_Map(0);
                    pMapDoc.SetActiveView((IActiveView)map);

                    pControlsSynchronizer.PageLayoutControl.PageLayout = pMapDoc.PageLayout;

                    pControlsSynchronizer.ReplaceMap(map);

                    pMapDoc.Close();

                    m_sDocumentPath = docName;
                }
            }
        }