1.8 - Add category tree to CMS page tab

Question

I have followed the guide here and created a custom tab on CMS Pages:

I now want to add a Category tree to this custom page. I have an answer here but I'm confused by this step:

In your form file where you add the tabs of your custom entity add this also:

$this->addTab('categories', array(
    'label' => Mage::helper('[module]')->__('Associated categories'),
    'url'   => $this->getUrl('*/*/categories', array('_current' => true)),
    'class'    => 'ajax'
));

I am not sure what is meant by "form file". Can anyone point me in the right direction?

Answer 1

It should be Tabs.php (Tab file) in the custom extension

You can see the following core file of catalog -> Manage product -> categories tab in admin panel

app\code\core\Mage\Adminhtml\Block\Catalog\Product\Edit\Tabs.php

Here you can see the same code:

$this->addTab('categories', array(
    'label' => Mage::helper('[module]')->__('Categories'),
    'url'   => $this->getUrl('*/*/categories', array('_current' => true)),
    'class'    => 'ajax'
));

That's it. Hope it help to you.