title: Seek Bar thumb not transparent in Android 5.0 API 21 Lollipop
body: <p>API Level &lt; 21 </p>
  
  <p>Thumb is transparent, as expected.</p>
  
  <p><img src="https://i.stack.imgur.com/OJGrZ.png" alt="Screenshot taken on a Nexus 5 running Android 4.4.4"></p>
  
  <p>On API Level 21</p>
  
  <p>Thumb is opaque, Wonder why.</p>
  
  <p><img src="https://i.stack.imgur.com/1tu0P.png" alt="Screenshot taken on a Nexus 5 running Android 5.0"></p>
  
  <p>Here is the code</p>
  
  <pre><code> &lt;SeekBar
                  android:id="@+id/ui_audioplayer_progressbar"
                  android:layout_width="match_parent"
                  android:layout_height="wrap_content"
                  android:progressDrawable="@drawable/custom_progress_bar_horizontal"
                  android:thumb="@drawable/stud_slider" /&gt;
  </code></pre>
  
  <p>Interestingly, this problem can be seen and reproduced in the xml preview in eclipse itself, when you change the API Level perspectives. </p>
  
  <p><img src="https://i.stack.imgur.com/MWmx4.png" alt="When API level 21 is selected"></p>
  
  <p><img src="https://i.stack.imgur.com/dKnQH.png" alt="When API level 19 is selected"></p>
  
  <p>Note: </p>
  
  <ul>
  <li>I run the same apk on both devices.</li>
  <li>Both devices are of the same make and model, i.e Nexus 5.</li>
  <li>The thumb image is a PNG with a transparent background, as apparent from the screenshot for API Level &lt; 21</li>
  </ul>
  
  <p>Is this a known bug in Lollipop or am i doing something wrong?</p>