I cleaner implementation (that actually follows spec) would be to set  
$XDG_CONFIG_DIRS to point to a different location (holding applications.menu).  

It's vitally important this get fixed before (wide) deployment of menu 
editors. 

Problem being that if/when anyone *does* use a menu editor, menus can (not
always?) end up blank.

Only workaround is to undo any previous menu mods:
remove/rename ~/.config/menus
run: kbuildsycoca

Have I mentioned this hack makes using $XDG_CONFIG_DIRS non-functional? (:

Here's the implementation I've been using for awhile now in kde-redhat packaging:

1.  Drop use of 
Patch7: kdelibs-3.4.0-menu.patch
which hard-codes use of /etc/xdg/menus/kde-applications.menu

2.  Use this snippet in kdelibs.spec:
## menus 
pushd $RPM_BUILD_ROOT%{_sysconfdir}/xdg/menus/
mv applications.menu kde-applications.menu
ln -s applications-merged kde-applications-merged
popd
## xdg.d/
mkdir -p $RPM_BUILD_ROOT%{_sysconfdir}/xdg.d/kde/menus
pushd    $RPM_BUILD_ROOT%{_sysconfdir}/xdg.d/kde/menus
ln -s ../../../xdg/menus/kde-applications.menu applications.menu
popd

You could alternatively simply move /etc/xdg/menus/applications.menu to
/etc/xdg.d/kde/menus/applications.menu and skip the symlinks (I don't think they
help backward-compatibility-wise anyway).

3.  Set $XDG_CONFIG_DIRS

I chose to do this in kdebase, creating
/etc/kde/env/kde-menus.sh
containing:
## from http://standards.freedesktop.org/menu-spec/latest/
# XDG_CONFIG_DIRS: where to look for menu config(s)
if [ -z "${XDG_CONFIG_DIRS}" ]; then
  XDG_CONFIG_DIRS=/etc/xdg.d/kde:/etc/xdg
  export XDG_CONFIG_DIRS
fi

It's not completely clear to me (from reading the spec) whether including
/etc/xdg explicitly in XDG_CONFIG_DIRS is absolutely required, but I figured it
doesn't hurt either.

it's fixed in new kdelibs-3.5.2-3/kdebase-3.5.2-7. Thanks for your report.

Arg, I see kdelibs-3.4.0-menu.patch is back, which effectively disables the use
of $XDG_CONFIG_DIRS.

I suspect kdelibs-3.4.0-menu.patch was reintroduced, because of reported crashes
due to its removal (notably from users who had previously used kmenuedit and had
~/.config/menu bits referencing kde-applications.menu).

ping, any comment?

I'm (still) receiving reports about kiosktool not working correctly due to this.

ok, i have reread the menu-spec. We should avoid adding of extra directories for
KDE menu. I think the correct fix is to use XDG_MENU_PREFIX as in menu-spec .

there's the fix

cat /etc/kde/env/env.sh
if [ -z "${XDG_MENU_PREFIX}" ] ; then
        XDG_MENU_PREFIX="kde-"
        export XDG_MENU_PREFIX
fi

install KDE applications.menu into /etc/xdg/menus/kde-applications.menu

The fix will be included in next kdelibs-3.5.4-9.fc6.

Nice, even better, thanks.

Your idea of trying to use XDG_MENU_PREFIX was a good one, but unfortunately
kdelibs didn't support it (as of 3.5.5).  I'll attach a patch recently applied
upstream to address that, so that we can try it out.

Created attachment 143053 [details]
upstream patch to enable use of XDG_MENU_PREFIX

yes i have seen the fix commited in 3.5 tree, it will be included in next 
kdelibs rebuild. I hope it will not cause any menu problem with 
XDG_MENU_PREFIX.

Anyway thanks for your attached patch!

I've confirmed that using XDG_MENU_PREFIX (with patch) now works as advertised.
 yay.