Module error message: MediabrowserUtility is not defined

If you install a custom module in Magento it could lack the TinyMce Mediabrowser. You get the following message then:

error: error in [unknown object].fireEvent():

event name: open_browser_callback

error message: MediabrowserUtility is not defined

How to fix this?

Quick fix

In /app/design/adminhtml/default/default/layout/YOURMODULE.xml add:

            1
            
            
            
            
            
            
            
            js_cssprototype/windows/themes/default.css
            js_cssprototype/windows/themes/magento.css
            lib/prototype/windows/themes/magento.css
            
        

Or change to

Long solution (may not work)

In your /YOURMODULE/etc/config.xml you have:

 
  <cms_wysiwyg_config_prepare>

      <variable_observer>
        core/variable_observer
        prepareWysiwygPluginConfig

In Block/Adminhtml/YOURMODULE/Edit.php

protected function _prepareLayout() {
    parent::_prepareLayout();
    if (Mage::getSingleton('cms/wysiwyg_config')->isEnabled()) {
        $this->getLayout()->getBlock('head')->setCanLoadTinyMce(true);
        $this->getLayout()->getBlock('head')->setCanLoadExtJs(true);
    }
}

Then in the top of Block/Adminhtml/YOURMODULE/Edit/Tab/Form.php

 protected function _prepareForm() {
            $form = new Varien_Data_Form();
            $this->setForm($form);
            $wysiwygConfig = Mage::getSingleton('cms/wysiwyg_config')->getConfig(array('add_variables' => false,
         'add_widgets' => false,
          'add_images' => true,
          'files_browser_window_url' => Mage::getSingleton('adminhtml/url')->getUrl('adminhtml/cms_wysiwyg_images/index'),
          'files_browser_window_width' => (int) Mage::getConfig()->getNode('adminhtml/cms/browser/window_width'),
          'files_browser_window_height'=> (int) Mage::getConfig()->getNode('adminhtml/cms/browser/window_height')
         ));

Further down:

$fieldset->addField('not-called-content', 'editor', array(
                                    'name'      => 'not-called-content',
                                    'label'     => Mage::helper('WHATEVER')->__('Content'),
                                    'title'     => Mage::helper('WHATEVER')->__('Content'),
                                    'style'     => 'width:550px; height:300px;',
                                    'required'  => false,
                                    'config'    => $wysiwygConfig,
                                    'wysiwyg'   => true
                                    ));

With thanks to Theodores