Well, I just installed Ubuntu 9.10 on my laptop (which I use as a kind of server, sitting behind my TV). I have connected the laptop to my TV through HDMI and I wanted to make it so that if I close the laptop lid, nothing happens. However, that option is simply gone in the power settings menu.
Now I can only choose Shutdown/Hibernate/Suspend or Blank Screen. However, the Blank screen option also affects my TV, leaving me with a nice black screen...
EDIT: Ive solved it. Cant figure out why on earth that option was removed.. Here is the solution:
In a terminal (Applications-->Accessories-->Terminal), type: gconf-editor
Navigate to apps-->gnome-power-manager-->buttons and set lid_ac and/or lid_battery to "nothing" (without the quotes).