Hey Herman, The zoom buttons work like you'd expect but, for VoiceOver users I haven't yet come across an instance where it's necessarily beneficial. It seems that VoiceOver sort of scrolls the window as needed when going through tracks.
A weird quirk in Pro Tools with VoiceOver is that the zoom button in the Edit window can sometimes appear to VoiceOver as being in the middle of the tracks view. So, if you move to the first item, instead of seeing the close and zoom buttons, you see Track 1, Track 2, etc. Somewhere after track 15 or so, you encounter a zoom button. I can't explain why that is and it also depends upon how many tracks you have, etc. Using the Item Chooser will help get to the zoom more efficiently but, again, I don't think it's particularly useful. HTH, slau
