I'm using FC1 with the latest gnome (and nautilus) from the development
tree of FC. GTK2-2.3.2.

I observed the following bug, which was also described here:

http://mail.gnome.org/archives/desktop-devel-list/2004-February/msg00003.html

1. Switch to a empty workspace. Focus one icon on the desktop.
   - the icon is selected and has focus (or the desktop has focus)
2. Right-click on the desktop, not on an icon.
   - at first a empty grey frame for the pop up menu appears
   - after some noticeable delay two things happen at the same time:
      - the icon (desktop) loses focus, it's selection turns grey
      - the pop up menu is populated with entries

This is the slow pop up menu. Now for the strange part, which might help
diagnosing the problem.

3.a Left-click somewhere on the desktop (not on an icon)
   - the pop up menu disappears
   - after about the same noticeable delay the icon (desktop) gets the
focus back

3.b Left click somewhere on the desktop (not on an icon) and before the
icon got its focus back, right-click again.
   - the pop up menu appears instantly.

3.c Have a nautilus window open on that workspace and right-click on the
desktop (not on an icon)
   - the pop up menu appears instantly.

In nautilus windows other than the desktop I didn't observe the above.

I also filed a bug with evolution, which exposes the same behaviour at
another place. You may want to have a look at that one, too.

http://bugzilla.ximian.com/show_bug.cgi?id=53697