Am running Fedora 18. I installed GNOME Tweak Tool from Fedora repository.

In the category "Desktop", the settings for:

2. Home icon visible on desktop
3. Trash icon visible on desktop
4. Show mounted volumes on the desktop
and possibly even 5. Network Servers icon visible on the desktop (not tested)

all of the above are valid and work only if the setting: 1."Have file manager handle the desktop" is enabled.

So, the above settings (2, 3, 4 and possible even 5) should be made insensitive if 1 is not enabled and vice versa. This would reflect the correct behaviour. This correct change would avoid confusion among users such as "Why won't icons show on the desktop despite enabling the settings?" Users may not be aware that these icons appear only when the file manager handles the desktop.