content: function updateConfig(params)
    config = params.config
    categories = config.categories
    host = config.host
  
    ' contentNode = CreateObject("roSGNode", "ContentNode")
    ' for each category in categories
    '   node = CreateObject("roSGNode", "category_node")
    '   node.text = category.title
    '   node.feed_url = host + category.feed_url
    '   contentNode.appendChild(node)
    ' end for
    ' m.category_list.content = contentNode
  
    for each category in categories
      button = CreateObject("roSGNode", "category_node")
      button.text = category.title
      button.feed_url = host + category.feed_url
      m.category_list.appendChild(button)
    end for
  end function
  
  sub onVisibleChange()
    if m.top.visible = true then
      m.category_list.setFocus(true)
    end if
  end sub
  
  function init()
    m.category_list = m.top.findNode("category_list")
    m.category_list.setFocus(true)
    m.top.observeField("visible", "onVisibleChange")
  
    button = CreateObject("roAssociativeArray")
  end function
  
  