  We study a $Al_{x}Ga_{x-1}As$ parabolic quantum wells (PQW) with
$GaAs/Al_{x}Ga_{x-1}As$ square superlattice. The magnetotransport in PQW with
intentionally disordered short-period superlattice reveals a surprising
transition from electrons distribution over whole parabolic well to
independent-layer states with unequal density. The transition occurs in the
perpendicular magnetic field at Landau filling factor $\nu\approx3$ and is
signaled by the appearance of the strong and developing fractional quantum Hall
(FQH) states and by the enhanced slope of the Hall resistance. We attribute the
transition to the possible electron localization in the x-y plane inside the
lateral wells, and formation of the FQH states in the central well of the
superlattice, driven by electron-electron interaction.
