altenbach -
My theory on why this is happening is because when you close the browser, you are not automatically logged out. You have to be inactive for a certain period of time for it to automatically log out you. If you open another browser and login again before your previous login has expired, you will show up in the Users Online list twice.
I will suggest that the Users Online display be intelligent enough to remove duplicate users when this occurs.
Thanks for the feedback,
Molly K.
Web Support & Operations Manager
National Instruments