This bit shows how Ableton Live 12's Play All probability group turns a percussion fill into an all-or-nothing event. Instead of individual hits randomizing on their own, the whole fill is grouped and assigned a single chance value, here set to 65 percent.
Each time the pattern loops, the entire fill either fires or stays silent, keeping its internal groove intact when it does play. That makes Play All useful for arrangement-level variation, like deciding whether a fill happens at all, rather than the note-by-note randomness you'd get from treating each hit independently.