title: ListView highlight item isn't shown
body: <p>I'm trying to highlight the currently selected item in a ListView. Below is the code I'm using; for some reason, while a similar code works perfectly in another ListView of this application, here the SelectedRectangle item is never displayed, althought the selected item changes when it should.</p>
  
  <pre><code>Rectangle {
      id: deviceTree
      width: (window.width * 2) / 3
      height: 400
  
      border {
          width: 2
          color: "black"
      }
  
      ListView {
          id: deviceTreeView
  
          model: deviceTreeModel
          delegate: deviceTreeDelegate
          highlight: SelectionRectangle {}
  
          anchors.fill: parent
          anchors.margins: 6
      }
  
      Component {
          id: deviceTreeDelegate
  
          Rectangle {
              border.color: "#CCCCCC"
              width: deviceTree.width
              height: 30
  
              smooth: true
              radius: 2
  
              MouseArea {
                  anchors.fill: parent
                  onClicked: { deviceTreeView.currentIndex = index; window.selectedDeviceChanged(deviceName) }
              }
          }
      }
  }
  </code></pre>
  
  <p>SelectedRectangle.qml</p>
  
  <pre><code>Rectangle
  {
      id: selectionRectangle
  
      color: "lightsteelblue"
      smooth: true
      radius: 5
  }
  </code></pre>
  
  <p>SOLUTION: The rectangle in deviceTreeDelegate was by default white and overlapped the selection rectangle. Using the property  it's set as trasparent so that the selection can be seen.</p>