sgr1

Hello everyone, I have just started to use ImgBurn. It is very nice. In my first burn the disc was automatically finalized; I think so because when I try to use the disc again I get "Disc not empty" error. How do I prevent this automatic finalization ? I do not want to waste a full DVD for one or several files. (By the way, I would expect that something so basic would appear in the Guides, but could not find any.) Thanks