Can't keep window up, it lowers itself while driving

I noticed a problem on the passenger side window of my 430 Scud, while driving it will move up and down repeatedly, very annoying. i can't keep the window rolled up all the way, it will just lower itself for 10 secs, then go back up, and repeat. however if I roll it down just a bit, it won't do this.

when the car is stationary with window all the way up, the door switch from inside and outside work just fine. when you tab the door opener, the window will lower itself to be ready for opening the door.

any idea?

Is there an adjustment that can be done to the window position? It seems like the pass window when rolled down, is a bit higher than the driver side. not sure if this is the cause.