When you upgrade your current ubuntu (11.10) to the new beta version, 12.04, you may experiencing with the problem especially on panel, shell and spread. To solve this problem, just simply type the following command on terminal,
unity-2d-shell
unity-2d-panel
unity-2d-spread
after that, you will get your panel, shell and spread work again. To make it work permanently when you boot to your new Ubuntu, type those commands on start-up application (Click right-top corner of your workspace). Let's try!
