Definitely a fringe case but thought I'd report it (I work in QA so it's almost a compulsion that I do so =oD)
On Win XP I use a little app called Taskbar Commander so that I can control the order and otherwise organize the items in my Windows task bar (the bottom bar with the Start button). When I run Taskbar Commander to move items around, the Performance Monitor is no longer hidden in the task bar and is displayed as 'Form1'. I can easily rectify this by Quitting then reopening PerfMon. I'm not sure if this is a Works As Designed thing or what but if it could remain hidden that would be great.
Incidentally, I'm beginning to notice how many little apps I have to run on XP just to get the kind of intuitive interface that is native on Linux distros. [2 ??:-|]