I have Outlook 2003 on Windows XP, Media Edition SP2

Sometimes I have a hidden session of Outlook. I can see it in my Windows
Task Manager window.

If Outlook is open, I'll have Outlook listed twice in the processes.

When I close Outlook, if I look in the Task Manager, it will show an Outlook
session still running.

I can't figure out what causes this. Could it happen from double-clicking
on the Outlook icon in the Taskbar?