The max_input_vars sets how many input variables may be accepted (limit is applied to $_GET, $_POST and $_COOKIE superglobal separately).

This parameter is set to 1000 (in some wordpress themes) and this may cause issues when saving the menu, so is recommend that you increase it to 2000 or more.

php.ini

max_input_vars = 2000

.htaccess

php_value max_input_vars 2000

Suhosin php.ini:

suhosin.request.max_vars = 2000

Suhosin .htaccess:

php_value suhosin.post.max_vars 2000

If Suhosin is not installed on your webserver you don’t need to use its parameters.