First of all congrats and thanx to the renoise devs for this new version… i really like it 
the mixer is great. it saves me alot of time with managing the volumes on the tracks…
UPDATE : nvm i just figured it out 
… it was window focus indeed (keyboard focus thing)
to the devs i have windows vista RC1 … part of the CPP program… so if you want me to test renoise in vista let me know … i know vista has some sound latency issues with the sound blaster xf-i beta vista drivers.
keep up the good work… this version is great! 