concatenating class instances?

Hi, Quick question. The below code snippet responded in a way that I didn't expect. I created an instance of the class frameWork, and then created an instance of the section class which is assigned to the same variable. I thought that the second instance would overwrite the frameWork object. Instead, I discovered that the frameWork object instead inherited the methods and properties of the new object, while maintaining the methods and properties of the old object. require_once('libraries/frameWork.php'); $frameWork = new frameWork; include('libraries/section.php'); $frameWork = new section; Am I correct to assume that this is the default behavior in the above circumstance? Thanks, Michael