I have only seen this happen once or twice in Karmic, and so far not at all in Lucid.
When it's happened, it has happened with the gnome system monitor. However, with Lucid I have has the Gnome System Monitor go up to 100% CPU a couple of times so far when I click on the applet to launch the monitor. So perhaps the issue is with the specific applet(s), and not Xfapplet.
I have only seen this happen once or twice in Karmic, and so far not at all in Lucid.
When it's happened, it has happened with the gnome system monitor. However, with Lucid I have has the Gnome System Monitor go up to 100% CPU a couple of times so far when I click on the applet to launch the monitor. So perhaps the issue is with the specific applet(s), and not Xfapplet.