If you are using Windows XP, set Dreamweaver as the default application. (Tools > Folder Options ... File Types....) Easiest way is to right click and specify the "Open With".."Select a program"... "Always use" and set Dreamweaver as your editor. I didn't have to make any changes to the File Type preferences in Dreamweaver so you might want to remove those to get this to work.
Personally I don't find Dreamweaver as the best XHTML editor and spend half my time in code view anyway. I do really like the CSS handeling and the fact that I know the app so well (makes things faster). Reading this thread I think I'm going to go checkout Nvu. Hope that helps Owen
