Don’t copy/paste! 
OT MKI/MKII page 80
It would be interesting to precise that zero crossing snapping depends on active view.
To select a zero crossing on both channels, you need to select both channels in CHANGE VIEW.
CHANGE VIEW changes the waveform visualization if a stereo sample is used. It is possible to visualize the left, right or both the left and right waveforms simultaneously.
Hold [FUNCTION] while moving the waveform, loop, start or end points to snap the selected point to a zero amplitude crossing. Zero crossings are indicated by a small rectangle in the middle of the marker. On very large Static samples there might be a short delay before the zero cross search is completed and the marker snaps in place.