Wrong $dolibarr_main_url_root in conf.php

[luckow]

If we package the app with
$dolibarr_main_url_root='http://localhost';in the conf.php, there are some weird phenomena in your daily work (e.g. if you submit some product variants, the button goal goes to localhost/path).
To make it right, we have to generate the correct main_url_root in the conf.php.