title: QComboBox text colour won't change with style sheet
body: <p>I'm trying to style a combobox in QT5. I'm using QT Creator for the layout and loading an app-wide style sheet at start up.</p>
  
  <p>The css I have related to my combobox is as follows:</p>
  
  <pre><code>QComboBox
  {
      color:white;
      background-color: qlineargradient(x1:0, y1:0, x2:1,y2:1, stop: 1 rgba(228, 41, 81, 100), stop: 0 rgba(234, 107, 101, 100));
      border-color: rgba(255,255,255,200);
      border-width: 1px;
      border-style: solid;
  }
  
  QComboBox QListView
  {
      border-style: none;
      background-color: qlineargradient(x1:0, y1:0, x2:1,y2:0, stop: 1 rgba(228, 41, 81, 100), stop: 0 rgba(234, 107, 101, 100));
  }
  
  QComboBox::drop-down
  {
      width: 20px;
      border: 1px;
      border-color:white;
      border-left-style:solid;
      border-top-style: none;
      border-bottom-style: none;
      border-right-style: none;
  }
  
  QComboBox::down-arrow
  {
      image: url(:/ArrowImages/images/whitearrowdown16.png);
      width: 16px;
      height: 16px;
  }
  </code></pre>
  
  <p>But the text colour in the combo box remainds as the default (black) colour. The colour in the drop down is white. The border colour and styling all work correctly. Is the label on the combobox some sort of sub-control I need to style separately? Or am I missing something else?</p>
  
  <p>Thanks.</p>
  
  <p>Edit:</p>
  
  <p>Added screenshots for clarity</p>
  
  <p><img src="https://i.stack.imgur.com/77jQB.png" alt="Combobox style"></p>
  
  <p><img src="https://i.stack.imgur.com/O3Nej.png" alt="Drop down style"></p>
  
  <p>Edit 2:
  It looks like this only occurs when the combobox is set to not be editable (which is the correct behaviour for my program, so doesn't really help me.) When the combobox is set to editable, it obeys styles correctly. I've tried adding</p>
  
  <pre><code>QCombobox:!editable
  {
      color:white;
  }
  </code></pre>
  
  <p>but it doesn't fix the problem.</p>