Comment 28 for bug 1562219

The workaround I used to fix the original problem as stated by the person who opened this ticket was to do the following:

chmod ug+s /usr/lib/xorg/Xorg

It seems in Ubuntu 14.04 the Xorg xserver binary has permissions of:

-rwsr-sr-x 1 root root 10192 Dec 9 2014 /usr/bin/X

so by running the above chmod command on the 16.10 (what I have installed) installed xserver binary does indeed fix the original poster's issue.