I have Dropbox installed on my Mac with OS X Lion 10.8.2. I don't use it often, so I eliminated it from the login item list. However, every time I open Dropbox from the application folder, it automatically add itself to the login item list. Is that normal, even if I locked changes? Can I prevent Dropbox to add itself to my item list every time I open it?
The idea of Dropbox is to always sync files across all your devices in the background. So disabling the login item doesn't really make sense from a Dropbox point of view. And at least at first glance I don't see significant drawbacks from keeping it there either.
If you just want to access some files in your Dropbox account you could use the web interface instead.