Sticky 5th gear fix
after selecting 5th gear, the gear lever fails to return to its normal position below 3rd gear. The problem is usually worse when cold. The cause is a defective coating on the bushing for the 5th gear locking pin, which causes the pin to stick in the bushing. BMW issued a repair kit that fixes the issue by replacing the bushing. Googling for "Gear lever sticks in 5th/reverse gear shift gate" should turn up a copy the service instruction. The repair kit itself costs all of £3 from a dealer, but replacing it is a fairly big job as it requires the transmission to be removed from the car.
http://www.ex-parrot.com/pdw/mcoupe/5th-gear-fix/index.html
Service Information https://webspace.ringling.edu/…ft_pins/sib230104-063.pdf