GDM message

[Jean-Baptiste Binet <jbbinet coframi-massy com>]

Hello.

When I open a session with GDM, if I close this session
immediately, there is a message box which says :
"Your session only lasted less than 10 seconds. If you have
not logged out yourself, this could mean that there is some
problem or that you may be out of diskspace.
..."

In documentation, I saw that it was a GDM security to allow
the user to see what happens if the session fails.
But, I would like to suppress this message box.
Could you tell me how to suppress it please ?
Thanks.

JB