Snap to Zero Crossing retrospectively? How

I have recorded a track using lanes and I have condensed 10 takes into one, with the snap to zero crossing tool disabled. I am not that clear on this tool though I do understand its outcome. It’s just how to apply the tool, retrospectively in this case
The track now has about 10 lanes, with the best bits selected from each lane about 25 parts. There are no gaps in timing between the individual parts. I want to get rid of some glitches.
Clickinmg and selecting two parts does not seem to function in hte lanes window. How does onw use Snap to Zero Crossing for this particular purpose please?

Z