Mapping many sliced sample to launchpad grid

I have a sample that I want to divide up to each pad on the launchpad. The problem is when I automatically slice the sample in the sample editor, although I can put as many slices in I want, only the 3 middle rows of the launchpad are mapped to slices. I tried to go into the keyzone editor and map manually but I am unable to do so. What am I missing? I assumed it would be with the “distribute” button but it’s greyed out. suggestions?