It seems, there in drivers for DM800SE is cosmetic bug. When is used stopService(), then is not cleared the framebuffer => there is still last picture frame and not black. May be, it is especialy, when is after stopService() used resize of desktop from HD to SD.
If i want clear framebuffer, i must make:
ref = self.session.nav.getCurrentlyPlayingServiceReference()
self.session.nav.stopService()
self.session.nav.playService(ref)
self.session.nav.stopService()
It seems, this bug is on DM800SE only,