The ^ operator doesn't seem to show up when used in <mover><mi>a</mi><mo>^</mo></mover> but does show up in <mover><mi>ab</mi><mo>^</mo></mover> Other operators like ¨ and ‾ seem to work
Marking as WORSKFORME since I am seeing the problem. Reporter, feel free to re-open if you still experiencing troubles.
I got even a problem displaying the ¨ operator with <mover accent='true'><mi>x</mi><mo>¨</mo></mover> whereas <mover><mi>x</mi><mi>¨</mi></mover></math> works fine.
Re: comment #4 Please provide build/date numbers when reporting problems. I see that particular problem in an old build, but not in a recent build. I suspect the problem was resolved afer my fix for bug 135940.