Sony CMT-CPX1 next track/fast forward selector opens CD door.

HI all!! I have a SONY MICRO Hi-Fi Component Unit Model No CMT-CPX1, and when I turn the selector for the next track on the CD, the CD tray opens, as if I had pressed the eject button. The same thing happens, when i try to fast forward a tape. The selector, as you can see in the picture, has multiple functions, depending on the selected source. It is like pressing 2 buttons at the same time. What could be the problem and how it could be repaired?