title: Show tooltip when the user selects item in QComboBox
body: <p>I want to show the tooltip with the text and the time when user selects the item in list view (hovers the mouse on the item in the list view) of <code>QCombobox</code>.</p>
  
  <p>I'm using a custom <code>QComboBox</code> with <code>QItemDelegate</code>.</p>