message: apply "collapsed" class&color to collapsed nodes
diff: @@ -172,7 +172,9 @@ export class PresentationNode extends React.Component<Props> {
  >
  {!rootNodes.includes(presentationNodeHash) && !onlyChild && (
  <div
  - className={defaultExpanded ? 'leaf-node' : 'title'}
  + className={classNames(defaultExpanded ? 'leaf-node' : 'title', {
  + collapsed: !childrenExpanded
  + })}
  onClick={this.expandChildren}
  ref={this.headerRef}
  >
  