Seek Bar thumb not transparent in Android 5.0 API 21 Lollipop

Question

API Level < 21

Thumb is transparent, as expected.

Answer 1

<SeekBar
    ....
    android:splitTrack="false" 
/>

Answer 2

For all API levels,

<Seekbar
    .....
    android:background="@null"
    android:splitTrack="false"
    ....
 />

will work. It worked for me.