  We present a density-functional theory (DFT) approach to the study of the
phase diagram of the maximum density droplet (MDD) in two-dimensional quantum
dots in a magnetic field. Within the lowest Landau level (LLL) approximation,
analytical expressions are derived for the values of the parameters $N$ (number
of electrons) and $B$ (magnetic field) at which the transition from the MDD to
a ``reconstructed'' phase takes place. The results are then compared with those
of full Kohn-Sham calculations, giving thus information about both correlation
and Landau level mixing effects. Our results are also contrasted with those of
Hartree-Fock (HF) calculations, showing that DFT predicts a more compact
reconstructed edge, which is closer to the result of exact diagonalizations in
the LLL.
