The cursor moves randomly while I use the trackball

Sometimes while I am using the track ball of my Logitech Marble Mouse the cursor moves randomly (to the left top corner of the screen mostly or other direction but closer to the original position).

I have two monitors at my laptop and sometimes the cursor jumps from the right monitor to the left top corner of the left monitor... preety weird!

I don't know if it is related to the optical sensor below the ball, but might be.

Any ideas?

Thank you very much. If I can solve it, I will post the solution here as well.