DG 300 landing gear

Well I finally done it. After checking that my gear handle was in the
proper position twice prior to landing, shortly after touchdown my
gear collapsed!
The only thing we could think is that the gear handle appeared to be
in the detent when it really was not. Further looking at it one can
actually miss the detent slightly, just before the actual notch and
still have the handle touching the side of the cockpit everything
looking just right. Somehow I guess one needs to lean over, look and
make sure it is in actually engaged, somewhat of a pain.
My question, is there any safety device available out there to prevent
this problem? PeterK