Jeff Green<jeff@kikisoso.org> (04/08/2010):
When starting up xclock with negative offsets to the geometry option, e.g.
xclock -geometry 120x240+-10+-10
xclock opens the window in the center of the display rather than
offset left and up by 10 (pixels).
strange. Using your command line exactly, I get the window aligned on
top& left. I assume the window manager is responsible for possibly
aligning instead of letting the window go off the screen.
However, if one forgets the '+' signs, stuff gets centered as you
described. Were you in that case?