Interactive Services

Interactive services generally poses several problems depending on the application and the Windows version as well.

Windows Version:
GUI applications may use visual controls from several libraries that ship with Windows. Some of these visual controls store data in a so called Global Atom List that is destroyed each time a user logs off. So it might happen that after a (re)logon some controls may look a bit damaged. But it seems that these problems are gone in newer Windows versions.

The Application May Terminate On User Logoff:
There are applications that do not handle certain system messages (WM_QUERYENDSESSION and WM_ENDSESSION for GUI applications or CTRL_LOGOFF_EVENT for console based programs) correctly. Those applications simply shutdown when the user logs off.
It's an easy task for the developers of such programs to provide a command line switch e.g. "-service" and handle the above messages in a different manner if the program is running in service mode.

Tray Icon Not Visible After Logon:
It's definitely caused by the application which doesn't restore its tray icon correctly. Although some applications do restore their icon under W2k and better they fail on Windows NT. Those applications listen to a system message (WM_TASKBARCREATED) that was introduced with Internet Explorer 4 and therefore will never be sent with older shell versions. A simple fix would be to restore the icon each time the taskbar is (re)created.

So what can you do?
Try to notify the developer of such applications about the problem so it can be fixed with the next release.