Fix for bug# 104258.

Dlg for setting to default mail should not appear when I'm composing a msg
r=ssu, sr=mscott

mailnews/mapi/mapihook/src/nsMapiRegistry.cpp

@@ -56,8 +56,11 @@ NS_IMPL_ISUPPORTS1(nsMapiRegistry, nsIMapiRegistry);
 
 nsMapiRegistry::nsMapiRegistry() {
     NS_INIT_ISUPPORTS();
-    m_ShowDialog = ! m_registryUtils.verifyRestrictedAccess();
+
     m_DefaultMailClient = m_registryUtils.IsDefaultMailClient();
+    // m_ShowDialog should be initialized to false 
+    // if we are the default mail client.
+    m_ShowDialog = !m_registryUtils.verifyRestrictedAccess() && !m_DefaultMailClient;
 }
 
 nsMapiRegistry::~nsMapiRegistry() {