  In this paper we study categories O over quantizations of symplectic
resolutions admitting Hamiltonian tori actions with finitely many fixed points.
In this generality, these categories were introduced by Braden, Licata,
Proudfoot and Webster. We establish a family of standardly stratified
structures (in the sense of the author and Webster) on these categories O. We
use these structures to study shuffling functors of Braden, Licata, Proudfoot
and Webster (called cross-walling functors in this paper). Most importantly, we
prove that all cross-walling functors are derived equivalences that define an
action of the Deligne groupoid of a suitable real hyperplane arrangement.
