I did what "bcdiesel" did & it worked beautifully! There was a lot of discussion about this problem a few years ago. Haven't heard much recently.
I popped the disc, with the shift pattern, out & made many slices, with a very sharp razor type knife, in the ridge of the disc that holds it in the knob. These slices create edges like what tread is to a tire. The "tread" holds the disc in place. I added one very tiny drop of silicone to the ridge just as an added measure to insure against rotation of the disc. It's still fairly easy to remove but, mine did not move after the "fix".
Joe