It really is. I made a final third sequence by adding first and second. Then I made some changes in sequence 2 and surprisingly the changes also showed in sequence 3 ! Finally, having last sequence active I exported it to a movie file and the result was exactly as I wanted.
So, it seems that VP works that way: clips make sequence, sequences make final sequence, final sequence makes movie. A bit weird but works.
Thank you Nationalsolo.
Regards,
Marbelan