Oh, I'm sorry. Only the xserver-xorg-core package doesn't cause this phenomenon. Actually it occurs on rebuilded package of 2:1.4.1~git20080131-1 on the present sid, though it doesn't occur on the same package downloaded from snapshot.debian.net. Maybe it occurs because of difference of dev library. After all, it was solved by typing of "startx -- :1". Thus, please close this bug. Regards, Hiroyuki