title: Transparency for overlapping views
body: <p>I have two views partially overlapping each other. They are both children of the same superview but don't have parent-child relationship between each other. </p>
  
  <p>Initialy viewA.alpha=1 and viewB.alpa=0 and then gradually I increase viewB.alpha which for some reason causes viewA to become more and more transparent though its alpha is still 1.</p>
  
  <p>How to change transparency for one of the overlapping views without affecting the others visually? </p>