I just tried it on El Capitan and I don't see the problem, but it has other issues (e.g. rio backdrop doesn't fill the 9vx window; full screen mode doesn't create its own desktop).
BTW, the 9vx I'm using has a date of July 1 2008. I'm sure some API's have changed underneath it.
I don't think I've ever been able to successfully compile 9vx from source.
-Skip