Had a similar problem I was able to correct as follows.
The handle has a rod that extends into the door and into the latch mechanism. The end of the rod is finished into a square where it inserts into the latch. The female recepticle of the latch is also square to accept the rod. In my case the rods square end had worn to almost round and this allowed it to flop down. It would hardly turn the latch. I pulled the handle and built the end of the rod back up with weld and ground it down to square.
It now stays level and works the latch as it should.
good luck
Dave
