Created attachment 126133 [details]
screenshot

so there is two topbar, one on the right local (french) and the other in C locale

That's what would happen if you had two nautilus extensions (.so files) in the directory. The one at the bottom looks like it's the old version, and the one at the top the new one.

I have only one burn .so in the system directory, could it be a conflict with jhbuild environment, (I don't understand why)?

baptiste@oak:~$ ll /usr/lib/nautilus/extensions-2.0/
total 448
-rw-r--r-- 1 root root  17932 2009-01-06 11:46 libevince-properties-page.so
-rw-r--r-- 1 root root  30436 2008-10-06 18:33 libgnome-mount.so
-rw-r--r-- 1 root root  22164 2009-01-09 08:06 libnautilus-brasero-extension.so
-rw-r--r-- 1 root root  22108 2008-12-18 14:31 libnautilus-burn-extension.so
-rw-r--r-- 1 root root  60408 2008-10-30 09:57 libnautilus-dropbox.a
-rw-r--r-- 1 root root   1627 2008-10-30 09:57 libnautilus-dropbox.la
-rw-r--r-- 1 root root  47236 2008-10-30 09:57 libnautilus-dropbox.so
-rw-r--r-- 1 root root  13704 2009-01-06 12:19 libnautilus-fileroller.so
-rw-r--r-- 1 root root  17936 2008-12-20 11:10 libnautilus-open-terminal.so
-rw-r--r-- 1 root root   9604 2008-10-21 20:01 libnautilus-seahorse.so
-rw-r--r-- 1 root root   9560 2008-10-09 00:29 libnautilus-sendto.so
lrwxrwxrwx 1 root root     45 2008-07-01 02:31 libtotem-properties-page.so -> /etc/alternatives/libtotem-properties-page.so
-rw-r--r-- 1 root root 171900 2009-01-09 12:56 libtotem-properties-page.so.gstreamer

baptiste@oak:~$ find /usr/ -name libnautilus-burn-extension.so
/usr/lib/nautilus/extensions-2.0/libnautilus-burn-extension.so
/opt/gnome/lib/nautilus/extensions-2.0/libnautilus-burn-extension.so
/home/baptiste/checkout/gnome2/nautilus-cd-burner/src/.libs/libnautilus-burn-extension.so

I think it might be loading both, passing on to nautilus which will do the actual loading.

Maybe due to:
-rw-r--r-- 1 root root  22164 2009-01-09 08:06 libnautilus-brasero-extension.so
-rw-r--r-- 1 root root  22108 2008-12-18 14:31 libnautilus-burn-extension.so

Duh. Yeah, that would be it.

Ah I didn't know brasero was prviding an extension too now.

sorry