gthumb 2.11.1 crashes on slideshow

Binary package hint: gthumb

gthumb 2.11.1 on ubuntu 10.04 lucid lynx alpha crashes every time I click on "slideshow".

Gdk-ERROR **: The program 'gthumb' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadAccess (attempt to access private resource denied)'.
  (Details: serial 48 error_code 10 request_code 2 minor_code 0)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)
aborting...

I don't know where to pass "--sync" on command line, it is not "gthumb --sync"…

ProblemType: Bug
Architecture: i386
Date: Sun Mar 7 12:39:38 2010
DistroRelease: Ubuntu 10.04
InstallationMedia: Ubuntu 10.04 "Lucid Lynx" - Alpha i386 (20100224.1)
Package: gthumb 3:2.11.1-2ubuntu1
ProcEnviron:
 LANG=fr_FR.utf8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-15.22-generic
SourcePackage: gthumb
Uname: Linux 2.6.32-15-generic i686