For a home user it not a problem, so it should been a options of course. Some prefer only use single screen, other dual screen.
Did you try to use a homepage component instead? It was only that way I got this resize problem to work, and even worked with all codecs (inclusive WMV). You can normally simple double click to change fullscreen/windowed mode (but not resize the window), and use javascript to control where the video was finsish. It was that, I did in blitz+.
Later I created a new Movieplayer dll in Pure Basic for better video integration in AMB, since its movieplayer worked like a dream. But some codecs diddent work on second monitor.
Hince I use both methods: "Homepage" for the second screen, purebasic for the first screen.
Sorry, I can't send you the dll, since PureBasic restrict that. Else I would do that!
If you want, you can use/change my source code for CDG, so you can use your own native player. It ok for me. it public domain.
We should have talked about this "issue" in the other thread by surf, since it more sence there. Sorry Surf.