Vega scrollbar

Do we still not have a scrollbar on Vega Visualizations ?

Is there some other way I can achieve to view the whole tree that I am trying to visualize on Kibana?

I am trying to build this Tree Layout Example | Vega on Kibana

What version of kibana are you using? It looks like @elastic/kibana#68766 closed @elastic/kibana#22240 as of 7.9.0. Is this sufficient for your use case?