Ha. Looks like you discovered a bug. I filed it here https://github.com/plotly/plotly.js/issues/1096. I’d recommend subscribing to this issue for the latest development info.
I believe the root of the problem is related to how legends and range slidesr impact the margin dimensions. So, to bypass that (buggy) algorithm, you can try setting the margin dimensions manually. I think I manage to get the desired results here: https://jsfiddle.net/74h1oq1k/2/ by setting layout.margin.t to some large value.