How to avoid flickering of background color of second window(w2) and directly show running mediaelement embedded in it. This Second window(w2) is called from main window w1?

Question

1. I have a main window w1. I create a window w2 with initial visibility as hidden.
2. I added a mediaelement inside w2 and added a media source to play.
3. As soon as media source is opened i want to make w2 visible on w1. w1 is also visible but it is underneath the w2.

Currently i am getting a short millisecond background color of w2 before video in it is started playing. I want directly media source on screen as soon as it is started playing.

Please help me to achieve it.

Thanks & Regards