  It is shown that the usual large-$N_c$ counting of the coupling constant
$L_{7}$ of the ${\cal O}(p^4)$ low-energy chiral $SU(3)$ Lagrangian \cite{GL85}
is in conflict with general properties of QCD in the large-$N_c$ limit. The
solution of this conflict within the framework of a chiral $U(3)$ Lagrangian is
explained.
