I have installed a gparted on my Debian and when I tried to run it as a root from the terminal the unexpected message has appear:
(gpartedbin:14177): Gtk-WARNING **: cannot open display: :0
Simple solution for this is:
- As a user (non root) type:
Message should appear:
non-network local connections being added to access control list
- As a root type:
Now you should be able to run your application. For me it works!