title: Change color of single QTabWidget tab
body: <p>I want to change the color of a single tab, please see screenshot below. The <code>FOO_SUP</code>tab should be red (right now only the button is), all others not.</p>
  
  <p><a href="https://i.stack.imgur.com/TVKxM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TVKxM.png" alt="Example"></a></p>
  
  <p>For the text color there is <code>bar-&gt;setTabTextColor(index, QColor(Qt::red))</code>, but not the whole tab. Setting the tab stylesheet for the tab widget changes the color of all tabs.</p>
  
  <p>I have found a stylesheet to change the tab color here: <a href="https://stackoverflow.com/a/21687821/356726">https://stackoverflow.com/a/21687821/356726</a> but not for a single tab, also I need to be able to decide at runtime if the tab is red or not.</p>
  
  <p>Just to make clear, the widget below shall remain black, the tab only red.</p>