Comment 10 for bug 738330

@Felix - I've found a package called virtualbox-guest-additions in the software center, but it doesn't sound like that's what you mean:

"This package provides an iso image which contains the guest additions for Linux, Solaris and Windows to be installed on the host system. The guest systems then can mount the iso and install the guest additions from there."

so that sounds like you're supposed to install it on the host. I can't find the package virtualbox-ose-guest-x11 in the software center but it installs from the command line (is there a reason that's not in the software center?).

So, after installing that, now I have the guest addition options like autoresize and seamless, but now my desktop has no launcher or panel, and if I try to start compiz from the terminal:

sam@sam-VirtualBox:~$ compiz --replace
Backend : gconf
Integration : true
Profile : unity
Adding plugins
Initializing core options...done
Initializing bailer options...done
Initializing detection options...done
Initializing composite options...done
OpenGL Warning: No pincher, please call crStateSetCurrentPointers() in your SPU
Initializing opengl options...done
OpenGL Info: Using XSHM for GLX_EXT_texture_from_pixmap
Initializing decor options...done
Initializing mousepoll options...done
Initializing vpswitch options...done
Initializing animation options...done
Initializing snap options...done
Initializing expo options...done
Initializing move options...done
Initializing place options...done
Initializing grid options...done
Initializing gnomecompat options...done
Initializing wall options...done
Initializing ezoom options...done
Initializing workarounds options...done
Initializing staticswitcher options...done
Initializing resize options...done
Initializing fade options...done
Initializing scale options...done
Initializing session options...done
** (<unknown>:1758): DEBUG: Unity accessibility initialization
Initializing unityshell options...done
** (<unknown>:1758): DEBUG: MaximizeIfBigEnough: Gnome-terminal window size doesn't fit
** (<unknown>:1758): DEBUG: PlaceEntry: Applications
** (<unknown>:1758): DEBUG: PlaceEntry: Commands
** (<unknown>:1758): DEBUG: PlaceEntry: Files & Folders

** (<unknown>:1758): WARNING **: Failed to fetch view type at /org/ayatana/bamf/window71303205: Method "ViewType" with signature "" on interface "org.ayatana.bamf.view" doesn't exist

terminate called after throwing an instance of 'std::bad_alloc'
  what(): std::bad_alloc
Aborted (core dumped)