Comment 3 for bug 1218360

Thank you for these details!

Just 2 others things:
Can you check if you have this bug with the latest stable version and/or with the development version. It's easy to install them simply by (temporary) adding our ppa (by using these commands):
* Stable:
    sudo add-apt-repository ppa:cairo-dock-team/ppa
* Development:
   sudo add-apt-repository ppa:cairo-dock-team/weekly

Then:
    sudo apt-get update
    sudo apt-get dist-upgrade

Also, do you have this bug if the dock is on the top/bottom of the screen (some Window Manager reserves spaces on the right/left of the screen)