install-info: warning: no entry Info into « /usr/share/info/gtkdialog.info.gz »

while upgrading some packages, i'm getting that error:

Processing triggers for man-db (2.7.0.2-5) ...
Processing triggers for install-info (5.9.96.dfsg.1-1) ...
install-info: warning: aucune entrée de répertoire Info dans « /usr/share/info/gtkdialog.info.gz »

Wonder if it is a gtkdialog bug instead of the reported texinfo above.
( used by multisystem : http://liveusb.info/dists/all/main/binary-i386/g/gtkdialog_0.8.3-2_i386.changelog )

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: install-info 5.9.96.dfsg.1-1
ProcVersionSignature: Ubuntu 4.0.0-3.5-generic 4.0.5
Uname: Linux 4.0.0-3-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 2.17.3-0ubuntu4
Architecture: i386
CurrentDesktop: GNOME
Date: Fri Jun 26 06:55:04 2015
SourcePackage: texinfo
UpgradeStatus: No upgrade log present (probably fresh install)