I've found what I believe is a bug in Outlook. I can demonstrate the problem
with the following code. It's a small add-in that hooks an event on the
Application
object. The problem only happens when the add-in is installed.

I've don't see anything wrong with this code. If anyone sees a problem
please let me know.

TIA, Tim

   public partial class ThisAddIn
   {
       private void ThisAddIn_Startup( object sender, System.EventArgs e )
       {
           try
           {
               m_application = Globals.ThisAddIn.Application;

               ( (Outlook.ApplicationEvents_11_Event)
m_application ).OptionsPagesAdd += new
Outlook.ApplicationEvents_11_OptionsPagesAddEventHandler(
onEvent_OptionsPagesAdd );

           }
           catch( Exception X )
           {
           }
       }

       private void ThisAddIn_Shutdown( object sender, System.EventArgs e )
       {
           try
           {
               ( (Outlook.ApplicationEvents_11_Event)
m_application ).OptionsPagesAdd -= new
Outlook.ApplicationEvents_11_OptionsPagesAddEventHandler(
onEvent_OptionsPagesAdd );

               m_application = null;
           }
           catch( Exception X )
           {
           }
           finally
           {
           }
       }

       private void onEvent_OptionsPagesAdd( Outlook.PropertyPages
PropertyPages )
       {
           return;
       }

       //

       Outlook.Application m_application;

       #region VSTO generated code

       /// <summary>
       /// Required method for Designer support - do not modify
       /// the contents of this method with the code editor.
       /// </summary>
       private void InternalStartup( )
       {
           this.Startup += new System.EventHandler( ThisAddIn_Startup );
           this.Shutdown += new System.EventHandler( ThisAddIn_Shutdown );
       }

       #endregion
   }