LinuxQuestions.org - Open programs don't appear on Gnome panel

I've been running Fedora Core 1 for about 2 weeks now, and am still adjusting after 10 years of using that other o/s! Anyway I've been switching programs using ALT+TAB, but have recently noticed that open programs no longer appear on the Gnome panel.

Now I can't remember precisely when this happened, and being a total newbie am having trouble re-tracing my steps. I'm sure (hopeful) that it's something trivially simple to fix, and would be very grateful to anyone who could shed some light on the matter.

Incidentally, when I minimize windows, the animation goes to the bottom-right hand side. I have tried re-arranging icons and the clock (thinking I may have hidden it??) but couldn't see anything. Is this significant?

Thanks in advance.