main_page.js

Todos.mainPage = SC.Page.design({
  mainPane: SC.MainPane.design({
    childViews: 'middleView'.w(),

    middleView: SC.ScrollView.design({
      hasHorizontalScroller: NO, //ADDED THIS
      layout: { top: 36, bottom: 32, left: 0, right: 0 }, //ADDED THIS
      backgroundColor: 'white', //ADDED THIS
      childViews: 'contentView'.w(),

      contentView: SC.ListView.design({
        contentBinding: 'Todos.tasksController.arrangedObjects',
        contentValueKey: 'description', //ADDED THIS
        contentCheckboxKey: 'isDone' //ADDED THIS
      })
    }),
  })
});