Applets, launchers, and everything else on the panel has an option in it's
context menu to lock or unlock it, allowing it to move around on the panel.

People find this unintuative and confusing as some applets (unlocked ones) will
move, while other applets (locked ones) will not.

Locking the taskbar however is quite useful as it prevents accidental moving of
applets. I propose changing to a global Lock/Unlock state. So that all context
menus (those on applets and those on the panel) have a menu option.

 x Lock Panel Objects
         or
   Lock Panel Objects

This should be per panel, and can obviously be stored in gconf. Panels should be
locked by default. Locking the panel shouldn't prevent you from explicity adding
launchers and applets with the "Add Applets..." button, however you shouldn't be
able to accidently drag anything onto the panel (does this work anyway?).

This will also resolve the usability problem of having the string change between
Lock/Unlock for each item. A string that is really confusing.