I prefer to use J feeders, with the tall part outside the cage and the trough through a hole in the side of the cage, suspended just a little above the cage floor. The only rabbit's I've had use these for potties are babies that figure it's easier to climb into the trough to eat rather than just sit up a little bit.
You might be able to discourage that behavior with a crock (bowl) if you suspend it a little higher from the side of the cage (just below where her chin normally is when sitting in a relaxed position). She won't be able to shove it around the cage then, either.
