Headers already sent. How to find the reason quickly
If you look inside of your Magento system.log from time to time, you will notice an error there like the following one:
2011-01-12T14:16:52+00:00 DEBUG (7): HEADERS ALREADY SENT: Call stack is here..
As you may already know, it can take a lot of time to find the place where the issues like this one appeared. So, let’s investigate why it happens and what we can do to speed up the bug fixing process.
How to add a new item to the navigation menu in Magento
Adding a new item to the navigation menu is fairly simple.
We will add this ability to a custom module. There is no need to modify core Magento files or templates and layouts.