title: User interface (how to change background)
body: <p>How i may change background for window?
  I have a Button, set <em>Style</em> "<strong>Round rect</strong>", set <em>Type</em> "<strong>On Off</strong>", set <em>State</em> "<strong>On</strong>"-how i may change background color from gray to blue?
  And how i may change background for all app?</p>
  
  <p>Thanks!!!</p>