User-Agent:       Mozilla/5.0 (X11; Linux x86_64; rv:5.0) Gecko/20100101 Firefox/5.0

System details:-
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Installation: openSUSE 12.1 (M4+) + GNOME:Factory
gnome-shell version: 3.1.4
zypper se -si gnome-tweak-tool
S | Name                  | Type    | Version    | Arch   | Repository
--+-----------------------+---------+------------+--------+-----------
i | gnome-tweak-tool      | package | 3.1.0-14.1 | noarch | GF        
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Setting the option of "Having the file-manager handle the desktop" on using the Tweak tool (Applications -> Advanced Settings, or gnome-tweak-tool from the terminal) forces the Fallback mode of GNOME3 on he next log in. Is not expected that switching this on would only cause icons to show up on the default GNOME3 desktop and for right-click on desktop to start behaving similar to nautilus? In fact this is what happens after switching the option on and before one logs out and logs back in, i.e. GNOME3 works with the usual goodness of dash, gnome-shell, etc. but only with icons showing up in the desktop. Hopwever once, a log out and log in in done, the user finds a Fallback mode instead. Switching the option off from Tweak tools and then logging out and re-logging back in causes GNOME3 to start up again in its full glory.

Reproducible: Always

Steps to Reproduce:
1.Open Tweak tools (gnome-tweak-tool)
2.Switch the option "Have file manager handle the desktop"
  in File Manager settings "On"
3.Log out and log back in
Actual Results:  
User finds a Fallback GNOME3 session instead of the default one.

Expected Results:  
Should see default GNOME3 session, but with icons and right-click on desktop.