I had the same problem and I was really annoyed by it. After reading this fix I have found even better and simpler solution:
Open up the "Compiz settings manager" and enable "Place Windows" plugin (part of the "compiz-plugins-default" package), click on it to go to its preferences and then in "Placement Mode" select menu chose "Centered". Since now every new window will be centered, and the problem of default (0,0) coordinated will be no more I hope it will be helpful to everybody who has this annoying problem -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-panel in Ubuntu. https://bugs.launchpad.net/bugs/707346 Title: Window/toolbar overlap in vertically stacked monitor configuration To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-panel/+bug/707346/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs