  The maximum-density-droplet (MDD) state of quantum-dot electrons becomes
unstable at strong magnetic fields to the addition of interior holes. Using
exact diagonalization, we demonstrate that the first hole is located at the
center of the dot when the number of electrons $N$ is smaller than $\sim 14$
and is located away from the center for larger dots. The separation between
field strengths at which additional holes are introduced becomes small for
large dots, explaining recent observations of a rapid increase in dot area when
the magnetic field is increased beyond the MDD stability limit. We comment on
correlations between interior hole and collective edge fluctuations, and on the
implications of these correlations for edge excitation models in bulk systems.
