I started “skinning” Magento today with a design that I was given. The functionality called for was a left category navigation (on every page but customer pages and cart/checkout pages) that always displayed the main categories – but when you click on a category, Magento should take you to that category’s listing, but also display the current subcategories.
So – since we all know that the Magento documentation is pretty crappy at this time, I had to do a lot of digging through core files, and a lot of time just with trial and error. But, I finally did come up with something that works. I’m willing to bet that there is a better, more proper way to do it, but regardless, this seems to be working perfectly.
What I did was create a new PHTML file, created the proper block call in page.xml, and now I’ve got a great working (and looking!) left-navigation. Here’s the home page (left), and a category page (right):