https://www.npmjs.com/package/@node-projects/web-component-designer-widgets-wunderbaum
npm i @node-projects/web-component-designer-widgets-wunderbaum
This package contains widgets using wunderbaum. This are more powerfull than the included ones in the designer.
then import the widgets:
import '@node-projects/web-component-designer-widgets-wunderbaum';
now you could use following widgets:
<node-projects-palette-tree-view></node-projects-palette-tree-view>
<node-projects-tree-view-extended></node-projects-tree-view-extended>