Upgrade to Ubuntu alpha or beta releases

If you want to upgrade to the newest and fanciest Ubuntu versions the easiest way is to enter this command:

sudo ubuntu-manager -d

In this case you don't have to alter /etc/apt/sources.list to the new version (for example from karmic to lucid) and then do a apt-get update && apt-get dist-upgrade. Also it removes some unused packages too.

Disappearing Gnome panel

If you have problems with disappearing panels after booting up the system, which can be caused by taking too long for restoring the session or because your system is slow anyway, there is a simple method to restore them: simply type

pkill gnome-panel

into the shell. After that the Gnome panel is restarting automatically!