work around GL drawing problem that appears in Snow Leopard (merge to 4.2.3)
work around GL drawing problem that appears in Snow Leopard (merge to 4.2.3)

svn: r16966

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket