Description:

In emacs-23.1-5, used together with the proof assistant Proof General (http://proofgeneral.inf.ed.ac.uk/),
the dynamically generated menus from Proof General (that is, the two menu items "Isabelle" and "Proof-General")
show completely empty. Interestingly this does not happen e.g. for the "TeX" menu item generated by AUCTeX, at least for me.

Steps to reproduce:
1. Download http://isabelle.in.tum.de/dist/Isabelle2009-1_bundle.tar.gz
(see this site: http://isabelle.in.tum.de/installation.html under "Linux")
2. tar -C /usr/local -xzf Isabelle2009-1_bundle.tar.gz
(this will only create a directory /usr/local/Isabelle2009-1 and its contents, as well as a soft link /usr/local/Isabelle to /usr/local/Isabelle2009-1, and nothing else)
3. Run the command:
/usr/local/Isabelle/bin/isabelle emacs
4. An emacs instance of Proof General will show up. Navigate with the mouse to either the menu item "Isabelle" or to "Proof-General" and see that the menus are empty.

Expected result:
non-empty menus

The same problem has been reported and fixed on the Ubuntu bug tracker:
https://bugs.launchpad.net/ubuntu/+source/emacs-snapshot/+bug/415101

The bug has apparently also been fixed upstream, at least this is what the discussion in the latter bug report says:
http://git.savannah.gnu.org/cgit/emacs.git/commit/?id=3715ffe3e3b2c64d113bf26d94aab559f8559e83

Workarounds:

Possibility 1: Inside Emacs, press F10 or run the command 'M-x menu-bar-open'. This will update the menus, so that they are not empty any more.

Possibility 2: Run
GDK_NATIVE_WINDOWS=1 /usr/local/Isabelle/bin/isabelle emacs
With this variable set to 1, the bug does not occur.

Further information:
I have tested some older emacs versions (down to 22.2) and the bug occurs in all of them. I just installed emacs-23.2 from [testing] and it does not exhibit this bug anymore. So should I even not submit this bug report? Forgive me if I shouldn't (I am not very used to making bug reports), but I think it at least interesting to note that the _current_ emacs version in [extra] has a bug and should be upgraded. If this is then irrelevant, please tell me and I will not make such bug reports in the future.

Cheers,

Malte