Forum:Ancient Gear Gadgetron Dragon vs. Skill Drain

A recent opponent of mine had an active Skill Drain on the field and an Ancient Gear Gadgetron Dragon on the field. H eattacked and i acitavted mirror force. He said I can't and stated skill drain doesn't negate Gadgetrons' effect because it's continous. I let it go (cost me the match) to avoid an argument. Now I need to know if Skill Drain does or does not negate Gadgetron Dragons effect and why?

pSkill drain says "negate the effect of all face uo monsters on the field". I kn ow continous effects don't activate but sense it's face up on the field, it should be negated. right?