I’ve been doing some intensive editing using the montage this week, and had two problems, each of which happened several times - I was too busy to derive an exact scenario, though - I probably could if necessary.
The “focus” issue relates to extreme horizontal expansion. I was editing right down at the sample level, and when reducing the magnification afterwards - which I do by swiping upwards from the ruler - very often the waveform display would go blank and the outline of the visible area on the navigator window would have jumped across to the far right (outside the audio - hence the blank display).
The crashes I can’t relate to anything directly. I was editing at quite a detailed level on one track of a montage (with a reference waveform in another track, locked and muted). What I was doing which I don’t normally do was fairly frequently swapping the files in the clips, using the File tab; as the files changed, I would save the montage under a new name. But I only ever had one montage open in WaveLab, although I accumulated a couple of dozen in the folder. Sorry I can’t be more specific yet.