Well ummm... M$ doesn't exactly document these features. In fact, the entire systray story is pretty much undocumented. You only get to know how your app can register an icon, but the sourcecode of the tray which handles the icons or of the windows taskbar is not really available... The DUN icon alone took months to get to work correctly. We're trying our best and we are aware of the windows update icon issue, but it's not like we could check MSDN to see how it works. If you know the solution feel free to send me an email.