Display a video/movie inside Waveform8

[Walli]

Hi,

I would like to display a video inside Waveform8, so that I can stay in sync - but it always says "no movie open" inside this display window.
I tried it with an mp4 and with an uncompressed avi (both play fine in windows media player).

Is this feature limited to certain codecs? I can´t find any hints inside the manual.

thanks!