Dragging connected nodes could be smoother

[lindavin]

When dragging nodes that are connected in Mist, there is a noticeable lag. Here is a demo in which it is smoother:

https://codesandbox.io/s/testing-line-drag-with-react-konva-bfxw1?file=/src/index.js

Dragging in Mist:
https://youtu.be/LXMgTiQn8gk

Ideal Dragging:
https://youtu.be/-m2muZp7w98

[lindavin]

Testing this more, I notice that after removing the menu layer can this lag is less apparent. It could be because the menu is rendering more often that it should.