[bug] Scrolling quirk in network graph mode

[nemesifier]

Describe the bug
In the network graph mode, if the user wanting to zoom scrolls on an area that falls outside the surface of the drawed graph, scrolling won't happen.

Steps To Reproduce

1. Open the basic example
2. Zoom out
3. Place the mouse far from the network graph
4. Try scrolling to zoom: zooming doesn't work

Expected behavior
In my opinion it would be better if the scrolling to zoom in/out would be similar to the geographic map: scrolling anywhere on the graph/map container will trigger zooming in/out.