The graded symmetry conjecture for the Soergel algebra of a block

Let $B_\xi$ be the graded Soergel algebra associated with the block $\mathcal O_\xi$ of $\mathrm{GL}(m|n)$.

Graded symmetry conjecture. The algebra $B_\xi$ is a graded symmetric algebra.

The conjecture concerns the additional symmetry of the Frobenius algebra structure on $B_\xi$ and is not resolved in the supplied text.