In latest Precise live system if I run any GUI command with sudo prefix, I get can not open display error message

[Hammer Attila]

I tryed gksudo gedit command. Unfortunately I get following error message:
Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",

Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",

Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",

Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",
Cannot open display:
Run 'gedit --help' to see a full list of available command line options.
ubuntu at ubuntu:~$

I forgotted prewious not need using sudo command in terminal to Orca 
prowide a11y support the root privilege launched application, because 
at-spi2 already prowide a11y support with gksu or gksudo launched GUI 
applications.
Oldest GNOME 2.x based releases Orca only prowide a11y support if the 
GUI application need launching root privileges if used the sudo 
applicationname command in GNOME Terminal.

Attila