public void UnregisterHandler(ContactHandler handler)
{
HashSet <ContactHandler> contactHandlers;
if (windowsMap.TryGetValue(handler.Handle, out contactHandlers))
{
contactHandlers.Remove(handler);
serviceCommunicator.RemoveWindowFromSession(handler.Handle);
if (contactHandlers.Count == 0)
{
windowsMap.Remove(handler.Handle);
}
if (windowsMap.Count == 0)
{
serviceCommunicator.RemoveSession();
}
}
}
