  The closure of a Diximier sheet is the image of a generalized Grothendieck's
simultaneous resolution. We show that the associated variety of simple affine
vertex algebras is contained in the closure of the Diximier sheet when a
chiralization of generalized Grothendieck's simultaneous resolution exists.
This generalizes in a conceptual manner the results obtained by the first named
author and Anne Moreau and, in particular, allows to extend them to the types
A_2, C_n, E_6, E_7.
