I do understand that. This is what I did:
I connected my plasma via scart cable and my hp lcd display via hdmi at the same time to my vu+. The result was that all animations worked on my HP, but they didn't work on plasma.
Same happened to XBMC. It all displays correctly on HP lcd, but it doesn't work on plasma via scart.
Please see the picture - it just doesn't make any sense to me.
I also created a specific thread for this, but nobody responded...