The WP Hide & Security Enhancer include a powerful functionality, the option to change the default new-login.php and the admin url with custom labels. This makes the administrative area for a WordPress site to become totally hidden for unadvised viewers. Compared to other available solutions (plugins and custom codes) the Wp Hide plugin use a different approach, which blocks the old urls making the dashboard inaccessible through those links, returning a default theme 404 error page.
In case of using another plugin or maybe theme which include a similar feature, making booth active may conclude to conflicts making login process not possible. Even if this can be easily restored, as no physical changes are done to any WordPress core files, this can still be a real fright sometime.
While using WordPress filters and following Codex recommendations should make everything to run smooth, there’s still certain code in form of plugins and themes which does not follow the good way, but take the dark path of hard-coding things. which obliviously create problems. While the WP Hide plugin use WordPress filters to implement all functionality, it should still work fine with a similar code which take the same usage of filters.
Generally the best approach to avoid any problems will be to chose a solution or another for changing the default login url. So you can either use the WP Hide and leave the other code / plugin inactive, either ignore the admin url change section and not fill any fields.