I've installed Debian 8 since a week, but I can not run any graphical application from console with the root user.Infact, when I run xampp (or any other program) I get the following errorroot# /opt/lampp/manager-linux-x64.runNo protocol specifiedNo protocol specifiedUnknown Error couldn't connect to display :0I've googled the error and tried any suggestion, but haven't solved the problem.This is my Xauthorityroot# echo $XAUTHORITY/root/.XauthorityThis is my DISPLAY variableroot# echo $DISPLAY:0The strange fact is that with my user (not the root one) I don't have any problem and I can run any graphical application.The DISPLAY variable is the same of the root one:user# echo $DISPLAY:0I also tried the suggestions here --> Why can't I run GUI apps from 'root': No protocol specified?:root# xauth + rootxauth: (argv):1:  unknown command +and the command export XAUTHORITY=~/.Xauthoritydoesn't have any effects 
No protocol specified: Unknown Error couldn't connect to display :0
debian;root;gui;display;xauth