I'm not sure if it's different when you log in remotely via mydlink, but by using the web based interface localy (by ip address) I can't find a way of exiting full screen option under live view.
I tried the obvious escape button. Right-clicking does nothing, and double clicking actually makes it truly fullscreen (aspect ratio gets stretched to my monitor 16:9 btw, instead of retaining 4:3.
So is there a way to exit? Using chrome, maybe it's a chrome issue and it works differently in other browsers but I see no mention in the manual of exiting fullscreen.
Edit: I just right-clicked on a non-video area and chose back and got out of it. Even though it would be rare, if this was hooked up to a 4:3 monitor (maybe someone would output to an old tv) there wouldn't be an non-video area to right-click.
If there is no current means, it should be escape or right click on video or something.