Category filters are not appearing in Layered Navigation. I am not using any plugin for layered navigation. Attribute and Price filters are appearing.
I have set Is Anchor and Show In Navigation to YES for all the categories. I have read other answers on stackexchange as well. No idea why this is happening.
In app/code/core/Mage/Catalog/Block/Layer/View.php (Line 207)
return $this->getChild('category_filter'); is returning NULL.