It's time to look for a real IDE for PHP. I've been spoiled by my past experience using Microsoft Visual Studio with intelliSense, which makes it so easy to find where functions are defined, etc. But, with PHP, I have not yet found an IDE that does such things for me. Lately, I've come across a tool called PHPStorm, which apparently has many of the goodies that are in Visual Studio. It costs $99, but it will probably pay for itself quickly.