Hello.The bug disappeared when I switched from xserver-xfree86 to xserver-xorg. Of course, this is a *major* change, and I won't commit myself to tell exactly what part of it solved the problem.
May be it was just something wrong with my configuration ; if noone is able to reproduce the bug, I suppose it can be safely closed.
'regards, Florimond -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]