Cannot run Graphical apps on Docker for Mac

Expected behavior

Following the steps described on this page:
(docker-tips/x11/README.md at master · chanezon/docker-tips · GitHub)

I expected to run Chrome or Atom inside a container. It works on the same host using Docker on an Ubuntu VM with no modifications.

Actual behavior

When running the container jess/chrome I get the following error and nothing shows up:
docker run -e DISPLAY=$DISPLAY_MAC -it jess/chrome
Failed to move to new namespace: PID namespaces supported, Network namespace supported, but failed: errno = Operation not permitted

Information

pinata diagnose -u
OS X: version 10.11.4 (build: 15E65)
Docker.app: version v1.11.0-beta8.2
Running diagnostic tests:
[OK] docker-cli
[OK] Moby booted
[OK] driver.amd64-linux
[OK] vmnetd
[OK] osxfs
[OK] db
[OK] slirp
[OK] menubar
[OK] environment
[OK] Docker
[OK] VT-x

Steps to reproduce the behavior

  1. Run ‘Proxying’ instructions described on URL above
  2. docker run -e DISPLAY=$DISPLAY_MAC -it jess/chrome
    Failed to move to new namespace: PID namespaces supported, Network namespace supported, but failed: errno = Operation not permitted