Comment 2 for bug 459117

unable to open display "localhost:0.0" persists.

Google "localhost:0.0" and you get 358,000 hits. Other than permission problems, this may be the most stumbled over mis-over-engineered feature is all of Linux. This is a severe and perennial usability problem.

In a clean Ubuntu 9.10 install, I can find zero tools to address the problem. If a third of a million people had enough of a problem with it to actually write to a news group, one could argue that millions have tripped over the same issue. Does this not scream out for an install option or some type of system tool like Applications->System->Fixed_FUBARred_LOCOHOST?

I found a bug report, Bug #370607, "X applications won't run under sudo", with similar results, but this problem has existed for years.
Bryce Harrington wrote on 2009-06-10:
I would first check gdm.conf... Next I would check what options are being specified on the X binary. Here's mine:
  /usr/X11R6/bin/X :0 -br -audit 0 -auth /var/lib/gdm/:0.Xauth -nolisten tcp vt7

`locate gdm.conf` -> /etc/init/gdm.conf. I have no line anything like this. Where is "-nolisten" being specified in this release? Is there any tool to configure the x server? Where?

When people have to spend many hours tracking down the latest implementation of these type of bugs, they get severely turned off on Linux.

    BrianP