i set active object to stop on collision with background plateform (TGF) but in one place the active object slips down into the platform for no apparent reason - drivin me mad - HELP!!
to start press any key ...... where's the ANY KEY??
Are you sure that the background in question has its Obstacle property set to "Yes" or "Platform"? (If you're using the second, try putting on Handle Background Collisions In Invisible Playfield on as well.)