Help! My Buttons! My Buttons!

So for the third time in six months the 'D' button of my shifter has jammed up. All the other buttons function as normal, and the trans shifts fine (except it won't go into Drive, of course)

Last two times, I "fixed" the problem by removing the trim panel, pulling the 'D' button out, and reinstalling it.

It seems like the button is jumping out of the slot and jamming up in the shift mechanism. Is there a more permanent fix? Could there be a clip or something that I'm missing? I'd like to not have to pull my dash apart every 3-4 months.