The irreducible-lattice conjecture for Property FW

Let $S$ be a semisimple connected Lie group with at least two simple factors and no compact factor. An irreducible lattice in $S$ is a lattice satisfying the usual irreducibility condition for such products. Property FW conjecture. Every irreducible lattice $\Gamma$ in $S$ has Property FW. This conjecture strengthens the known result that these groups have Property FA, proved by Margulis, and predicts a fixed-point property for actions on spaces with walls; its status is not resolved in the supplied source.