To put it simply - you can’t remove timestamps from date LoV’s. If you plough through multiple historical questions on this forum you will find that there isn’t a solution to this, TRIM, LEFT…10, TRUNC. None of these work for LoV’s, so don’t spend any more time trying to get them to work. Yes it should be simple and it should be achievable, but it isn’t.
There is also FAQ on the Designer Forum
dessa 
(BOB member since 2004-01-29)