Multiple roots support

[Maximaximum]

Is your feature request related to a problem? Please describe.
I'm trying to render a tree with multiple roots (ie, render multiple trees in a single component), but I get a 'multiple roots' error.

Describe the solution you'd like
It would be great if we could render multiple roots on the same component, so that all the root nodes are located at the same top level of the hierarchy.

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[bumbeishvili]

Org chart cannot have multiple roots (a.k.a. two parents for a single node)

If you just want multiple nodes displayed at the top, create a dummy node data which will be the parent of these nodes, and then hide this node and link with CSS or inside in nodeUpdate & linkUpdate methods

[bumbeishvili]

Here is a sample - https://stackblitz.com/edit/js-qm3aga?file=index.html