correct description of vb option

git-svn-id: svn://svn.code.sf.net/p/vpinball/code/trunk@891 14438d79-0ffd-4333-8ae7-ea2bdd901387
hopefully fix some top window issues with vpinmame

git-svn-id: svn://svn.code.sf.net/p/vpinball/code/trunk@892 14438d79-0ffd-4333-8ae7-ea2bdd901387