title: Set different color to specifc items in QListWidget
body: <p>I have a <code>QListWidget</code> and I want to add border bottom to each item of the list and set a background color to items and I want to set to specific items a different background color.
  So I used <code>my_list.setStyleSheet("QListWidget::item { border-bottom: 1px solid red; background-color: blue;}")</code> and to set background color to specific items I used <code>item.setBackground(QtGui.QColor("#E3E3E3"))</code></p>
  
  <p>The problem is the specif items that I set a different color don't get this color.</p>