title: Changing Actionbar Background programmatically in one activity, changes in whole application
body: <p>my problem is simple, it is relative to only Lollipop 5.0</p>
  
  <p>I have a main activity where I set a certain theme then I set programmatically a custom background to the actionbar:</p>
  
  <pre><code>        context.getActionBar().setBackgroundDrawable(context.getResources().getDrawable(
                  getCustomColor(context, Theme)));
  </code></pre>
  
  <p>Then I open another activity, where I set my custom theme, and my custom background drawable, this time made traslucent:</p>
  
  <pre><code>    mActionBarBackgroundDrawable.setAlpha(0);
      context.getActionBar().setBackgroundDrawable(
              mActionBarBackgroundDrawable);
  </code></pre>
  
  <p>When I press back, if finishes the activity correctly but then my main activity has the actionbar completely transparent!
  It is as if changing the background of the actionbar in my 2nd activity, changes it also to the 1st one!</p>
  
  <p>It works correctly from android 4.0 to 4.4.4</p>
  
  <p>Can you help me?</p>
  
  <p>Thanks and regards</p>