In a fresh XFCE 4.6.2 install (Gentoo IA32), when right-clicking on
the desktop, the new top-level menu always appeared instead of the
application menu even though the desktop->icons->Icon_type was set to
None.  (Which is what everybody claimed was the solution for people
who wanted to skip the top-level menu and see the application menu on
right-click.)

Enabling and disabling the four default icons didn't help.

After messing around re-building stuff for a couple hours, I finally
happened to set "Icon type" to "File/launcher" and then back to "None".

That fixed it.  The application menu appears on right-click.

I've since found various other reports of the same behavior: Just
having "Icon type" set to "None" doesn't do the trick.  You've got to
enable icons, and then subsequently disable them before the
application menu shows up.

One thing that might be significant is that the first few times I
started xfdesktop, it crashed due to an xfconfig/dbus assert failure
because I wasn't in the plugdev group -- not that the error messages
gave any indication to the source of the problem.  That took quite a
while to figure out.

After I added myself to the plugdev group and restarted dbus,
xfdesktop startup up OK, but then I ran into the right-click,
application-menu problem.