After a deep investigation and many many experiments, my conclusion is that the actual version (without my patch) seems to work well, with only one exception: the bottom-right notification that appears the first in a session shows misplaced (too down in the screen). However, subsequent notifications appears correctly.
Therefore, it seems that the problem is not in the width or height calculation, but in the Y position the first time the library needs to show a notification. The notifications that appears in the top of the screen (update-notifier or rhythmbox) don't seem to have this problem. I attach screenshots to illustrate the problem. ** Attachment added: "update-notifier's bubble, shows ok without my patch" http://librarian.launchpad.net/3024423/1.png ** Attachment added: "The first notify of the session appears misplaced" http://librarian.launchpad.net/3024428/2.png ** Attachment added: "Screenshot after a second "notify-send" execution" http://librarian.launchpad.net/3024431/3.png ** Attachment added: "Screenshot after closing all the bottom bubbles and executing a third "notify-send"" http://librarian.launchpad.net/3024432/4.png -- Notification bubble shows sometimes wide, sometimes narrow https://launchpad.net/bugs/45656 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs