I had an existing JJ2 1.23 folder somewhere where I could not enter fullscreen mode. I updated Plus on it. (it had an Oct. 2010 build). Still no fullscreen option. Then ran the dll from this page, still no fullscreen option. Relaunched JJ2+ again and it launched directly into fullscreen and all the DDRAW options were present. Ran JJ2+ several times and they were still present. Ran JJ2 vanilla from that same folder and there were no fullscreen options. Ran JJ2+ again and there were fullscreen options. Renamed the folder and ran JJ2+ and the options were still present.

Hope this helped.