php - My SilverStripe module overrides other modules display -

i'm writing subscribe module plugin silverstripe blog module. far have yml as:

--- name: subscription after: 'framework/*','cms/*' --- blog:   extensions:     - subscription page_controller:   extensions:     - subscriptionwidget 

and subscriptionwidget.php:

<?php class subscriptionwidget extends dataextension {      public function subscriptionwidget() {         $controller = subscriptionwidget_controller::create();         $form = $controller->subscriptionwidget();         return $form;     } }  class subscriptionwidget_controller extends controller {     private static $allowed_actions = array('subscriptionwidget');      public function subscriptionwidget () {         $form = form::create(             $this,             __function__,             fieldlist::create(                 textfield::create('email', 'email'),                 textfield::create('name', 'name')             ),             fieldlist::create(                 formaction::create('submit', 'subscribe')             )         );//->settemplate('subscriptionwidget');         return $form;     }      public function submit($data, $form) {         return $this->redirect('/subscribed');     }  } 

at moment works intended plugin use called betternavigator disappears screen. if take out

page_controller:   extensions:   - subscriptionwidget 

from yml reappears. i've looked through both code bases quite simple , there no conflicting functions. i've tried using contentcontroller instead of page_controller , template disappears until disable betternavigator , reappears. have 1 or 2 pretty empty classes called variation of subscriber while there 1 function in betternavigator called betternavigator.

why happening?

i see 1 clash in code results in incorrect runtime behaviour. method subscriptionwidget::subscriptionwidget() treated legacy class constructor. suggest thinking better class , method names.

class subscriptionwidget extends extension {     // explicitly defined constructor     public function __construct() {         parent::__construct();     }      // 1 normal function     public function subscriptionwidget() {         $controller = subscriptionwidget_controller::create();         $form = $controller->subscriptionwidget();         return $form;     } }