title: Panel background not being changed by UI manager
body: <p>In my program I would like the user to be able to change the colour scheme of the program. I have a method which passes in a colour to set the background of all the panels using UIManager.</p>
  
  <pre><code>public void changeColourScheme(Color c) {
          UIManager.put("Panel.background", c);
          SwingUtilities.updateComponentTreeUI(this);
      }
  </code></pre>
  
  <p>However the issue I'm running into is that it is not changing the colour of the panels. This method is located in the class for the JFrame.</p>