There's an action OpenDefinitionActionDefinition which currently only opens the overview subapp, but doesn't highlight the corresponding definition node.
This is related to opening detail locations not working properly in the definitions app in general.

Action bar definiton to be re-added afterwards:

    actionbar:
      sections:
        file:
          groups:
            default:
              items:
                - name: showDefinition
          availability:
            rules:
              IsFileDefinitionRule:
                implementationClass: info.magnolia.definitions.app.overview.availability.IsDefinitionRule

Before integrating

Make sure CFGUI-50 is integrated first and this one rebased properly on top of it.