title: Qt: Applying stylesheet on QScrollArea making horizontal scrollbar disappear but working perfectly for vertical scrollbar
body: <p>I am trying to apply some style-sheet for scrollbars of QScrollArea and my style sheet as follows.</p>
  
  <pre><code>QScrollBar:vertical {
  
    border-color: rgb(227, 227, 227);
    border-width: 1px;
    border-style: solid;
  
    background-color: rgb(240, 240, 240);
    width: 15px;
    margin: 21px 0 21px 0;
  }
  
  QScrollBar::handle:vertical {
  
    background-color: rgb(200, 200, 200);
    min-height: 25px;
  
  }
  
   QScrollBar::add-line:vertical {
      border: 1px solid grey;
    background-color: rgb(241, 241, 241);
      height: 20px;
      subcontrol-position: bottom;
      subcontrol-origin: margin;
  }
  
  QScrollBar::sub-line:vertical {
      border: 1px solid grey;
      background-color: rgb(241, 241, 241);
      height: 20px;
      subcontrol-position: top;
      subcontrol-origin: margin;
  }
  
  
    QScrollBar::add-page:vertical, QScrollBar::sub-page:vertical {
        background: none;
    }
  
  QScrollBar::up-arrow:vertical
  {
    image: url(:/BarIcon/Icons/uparrow.png);
  }
  
  QScrollBar::down-arrow:vertical
  {
    image: url(:/BarIcon/Icons/downarrow.png);
  }
  
  QScrollBar:horizontal {
    border-color: rgb(227, 227, 227);
    border-width: 1px;
    border-style: solid;
    background-color: rgb(240, 240, 240);
      width: 15px;
      margin: 0px 21px 0 21px;
   }
  
   QScrollBar::handle:horizontal {
      background-color: rgb(200, 200, 200);
      min-height: 25px;
   }
  QScrollBar::add-line:horizontal {
      border: 1px solid grey;
    background-color: rgb(241, 241, 241);
      width: 20px;
      subcontrol-position: right;
      subcontrol-origin: margin;
   }
  
   QScrollBar::sub-line:horizontal {
    border: 1px solid grey;
      background-color: rgb(241, 241, 241);
      width: 20px;
      subcontrol-position: left;
      subcontrol-origin: margin;
   }
  
   QScrollBar:left-arrow:horizontal
  {
    image: url(:/BarIcon/Icons/leftarrow.png);
  }
  
  QScrollBar::right-arrow:horizontal 
  {
    image: url(:/BarIcon/Icons/rightarrow.png);
  }
  
  QScrollBar::add-page:horizontal, QScrollBar::sub-page:horizontal {
       background: none;
  }
  </code></pre>
  
  <p>This stylesheet perfectly does what it was supposed to for vertical scrollbar but with presence of any single stylesheet related to <code>QScrollBar:horizontal</code>, the bar just disappears.</p>
  
  <p>Please can anyone point out my flaw and what should I do?</p>
  
  <p>Notes:
  The styleSheet have been applied on QScrollArea object by using <code>Change styleSheet</code> option of Qt Designer.</p>
  
  <p>And please kindly acknowledge in case where the horizontal scrollbar shows up with this styleSheet on.</p>