there is a nice rubber mount on the linkage that the shifter ball rides in, and when that mount goes bad, the shifter will drop out of the hole.
kind of a bad design on mazda's part, cause its the design of the bf chassis 323. why they designed it like that, i will never know.
but if this ever happens to joe(rci) i want to see if we could mod up a civic/integra stabilizer bar. which uses a 2 bolt plate to hold the shifter in the stabilizer bar. then a 2 bolt mount at the back of the stabilizer and then the trans mounting point.