I was testing this again with the X11 included with Leopard and this is what I see after X11 is up and running in two different accounts, merle and testme. testme% ls -la /tmp/ total 16 drwxrwxrwt 11 root wheel 476 Dec 16 13:01 . drwxr-xr-x@ 6 root wheel 204 Dec 16 11:32 .. -r--r--r-- 1 merle wheel 11 Dec 16 12:59 .X0-lock -r--r--r-- 1 testme wheel 11 Dec 16 13:01 .X1-lock drwxrwxrwt 2 merle wheel 136 Dec 16 13:01 .X11-unix srwxrwxrwx 1 merle wheel 0 Dec 16 12:18 com.hp.launchport drwx------ 2 merle wheel 102 Dec 16 12:18 launch-4hKjbV drwx------ 2 testme wheel 102 Dec 16 12:19 launch-5F6kkF drwx------ 2 merle wheel 102 Dec 16 12:18 launch-7Z6e7z drwx------ 2 testme wheel 102 Dec 16 12:19 launch-Bpwd9y drwx------ 2 merle wheel 102 Dec 16 12:18 launch-RxHKBP drwx------ 2 testme wheel 102 Dec 16 12:19 launch-UTIeyp drwx------ 2 merle wheel 102 Dec 16 12:18 launchd-146.fUrw5l drwx------ 2 testme wheel 102 Dec 16 12:19 launchd-210.x7HrLe testme% ps -axww | grep -i x11 316 ?? 0:00.03 /usr/X11/X11.app/Contents/MacOS/X11 317 ?? 0:01.02 /usr/X11/X11.app/Contents/MacOS/X11 -auth / Users/merle/.Xauthority :0 334 ?? 0:00.03 /usr/X11/X11.app/Contents/MacOS/X11 335 ?? 0:00.63 /usr/X11/X11.app/Contents/MacOS/X11 -auth / Users/testme/.Xauthority :1 352 ttys002 0:00.00 grep -i x11 So, it would appear that in the original Leopard X11, that X11.app is somehow seeing that it should use a different display. Merle