connected taxonomy selection

This plugin doesn’t generate the meta boxes for taxonomies, it lets WordPress run its default meta boxes. I also have no intentions on changing this behavior, because I want this plugin to be small, light, fast, focused, and defer to the WordPress core whenever possible.

That said, if you want a different UI for interacting with your taxonomies, because the taxonomies are not manipulated in any way, you can leverage the scores of plugins out there that manipulate the taxonomy meta box or you can cook up your own. Or you can use this plugin to add a meta box, and add the fields dynamically or using dynamic data. Check out this article to get you started.