Steps:

1. Create a palette with a tiny row and column size, say 2x2
2. Use color sampler, select said palette, toggle 'add to palette'.
3. Now, select more colors than there are slots in the palette, for our example, that'd be 5. Note that the palette docker takes a bit to update.
4. Go into Edit Palette Dialog, increase row and column count.
5. Observe that the extra colors that had been picked are now shown.

Expected result:
I would expect the group row count to be increased if more colors are added than it has slots for.