Betty, I've noticed that my microwave glass tray will shift a bit, but I put bread up there too, or whatever needs a "storage" area while we are moving and something that's not heavy as to cause problems.
I have SO much storage in our Cyclone. There are quite a few "cupboard doors" and I love telling people that they are ALL functional. In fact, I don't have them all in use. I have more storage in the Rv than I do in my kitchen.
The only downside of it is to reach ANYTHING I have to stand on a chair. I've heard that can be a dealbreaker for some people, but they have to expect some "high up" if they are wanting lots of storage. I don't mind having to use a chair (except for the morning the seat swiveled on it and I fell off................LOL). The SU is always after me when I do that..........."don't stand on the chair, you're gonna fall off". Me..........."no, I won't". He was still in bed when it happened. I'm surprised he didn't come to see what happened, as I really made a clatter when I fell.