D3 drag jitters when I .call(zoom)
on two overlapping elements - and try to drag on the top element.
Here is an example http://codepen.io/anon/pen/WbNjqg
In this case, zoom has been registered on the chart's bars and on the chart's background.
I can't add an invisible rectangle over the entire chart to register the zoom because that element would prevent mouseovers from registering on individual bars.
Why does this shaky horizontal scrolling occur - and how can I fix it?