What kind of glass is in this window? If it weighs considerably less that the original, the compensating spring in the winder mechanism and vibrations from driving may be enough to lift the window. Just a thought???
Joe B
on your window regulator, there is a spring brake that hold the window in place. if that part of the spring is broke. the main regulator spring will over ride and make the window go up.that spring is located under the regulator gear cover.