Go to the last question in the manual PlayTest and do the following:

  - Click on the slider and seek forward
  - Click on the Play button

If the media is in a stop or pause state from the very beginning and then you try to seek forward, it does not work. The play state has to be called first before the seek works. Even at this point, it will only work while in the play or pause state. It will never work in the stop state.

I believe if I seek to a position that is available no matter what the player state is, it should seek to that position as soon as Play() is called. Also, there should be a little more detail as to when seek() can be used in the documentation.