Drupal: edit Content inside Backend-Theme (See related posts)

/* If you've configured Drupal (www.drupal.org) the way that it
uses different themes for the frontend and the backend, it still kicks
you into the frontend when you edit content.
To change this you have to edit this file:
modules/system/system.module

at the end of the function "function system_menu($may_cache)" look
for the "else" part
*/

// in line ~308
// find:
if (arg(0) == 'admin')

// repalce with:
if (arg(0) == 'admin'||
(arg(0)=='node' && arg(1)=='add') ||
(arg(0)=='user' && arg(1)!='') ||
(arg(0)=='node' && (arg(2)=='edit' || arg(2)=='localizernode'))
)