Trouble With Sproutcore Template Views inside Core

followup.handlebars

<div>
  Hello, <b>{{text}}</b>!
</div>

main_page.js

mainPane: SC.MainPane.design({
    text: "world",

    childViews: ['mainToolbar','followUp'],
    
    mainToolbar: SC.ToolbarView.design({
      ...
    }),

    followUp: SC.View.design({
      layout: { width: 200, height: 30 },
      childViews: 'template'.w(),

      template: SC.TemplateView.design({
        templateName: 'followup',
        textBinding: "parentView.parentView.text"
      })
    })
  })