text: Q:
  
  Styling ::tab of a QTabBar element results in style lose
  
  In my application, I want to style the selected tab of a QTabBar element. What I style is only its background-color, but every time I change its background-color attribute, all the other styles are immediately lost.
  At first I thought it was an issue only for background-color's, but then trying more I noticed that even by changing the margins of the tabs, all the other styles are lost. The background-color of the other tabs is set to transparent, padding and borders lost too.
  I think that the correct way for QT to behave, should be to leave untouched the attributes that I have not explicitly modified, but for such an obvious behaviour not to be implemented there have to be other reasons or I am missing something.
  Is this an actual “bug” or is there something that I did not consider when trying to styling the tabs? 
  
  A:
  
  I believe the issue that you are running into is that once you alter the style of a GUI element, Qt can no longer draw it using your OS's native controls.
  When you alter the style of any kind of native widget (tabs, combo boxes, etc), you should be prepared to take manual control of the style for every aspect of that widget since you are saying that you don't want it to look like a native widget anymore, and Qt has to use a different underlying painting system for rendering the widget.
  
  