Root Terminal cannot start graphical applications

Note: this only affects the Root Terminal provided by the gksu package.

When I try to start e.g. synaptic:

root@amnesia:/home/amnesia# synaptic
No protocol specified
Unable to init server: Could not connect: Connection refused

(synaptic:15100): Gtk-WARNING **: cannot open display: :1

So it seems the hack for #12000 (closed) is not working any more.

This doesn’t affect Tails 3.1, but affects builds of devel at least as of 2017-08-14.

Related issues

• Blocks #12034 (closed)
• Blocked by #12738 (closed)

Original created by @anonym on 13625 (Redmine)