Code review comment for lp://staging/~sacridex/ubuntu/precise/unity-greeter/purple-background-on-startup-fix

Because the guest account has no image.
If a user has no background(which I think is impossible, but who knows), the default_background is used(background.vala:447). This is the backgroundcolor set for the lightdm user(background.vala:230).
So the guest account has a background image after all, and not just the background color.

But thinking about it now, it would be a better solution, not to put the "*other" user into the user_list at first(user-list.vala:257), but checking if there are any users in the user_list, after the real users have been added to the user_list(if not, then put "*other" to the user_list).