I guess the point is it can't be sandboxed by directly exposing X protocol messages to the sandboxed app. Although your sibling comment by gpderetta makes an ex

I guess the point is it can't be sandboxed by directly exposing X protocol messages to the sandboxed app. Although your sibling comment by gpderetta makes an excellent point. I guess they're saying no one wants to sandbox the X protocol, and breaking compatibility, proponents would claim, lets you design a sandbox friendly protocol from scratch.