Changes

==Introduction==

In this walkthrough, we will explore the process of making a small change to the behaviour of Firefox. The change we will make will be done directly in the Firefox source code (note: this change can also be done as an extension, which we will do in another walkthrough). In so doing, we'll learn how to go from an idea for a top-level UI feature change, to searching and studying the code, to making and testing this change.

The goal of this exercise is to give you confidence in order to try similar things on your own, expose you to some helpful techniques, and to highlight the importance of using existing code in open source and Mozilla.

'''NOTE:''' === Getting the Source === All sample code listed in this walkthrough was taken from [http://hg.mozilla.org/mozilla-central/file/f4800de50e03 mozilla-central revision f4800de50e03]. Newer versions of Later changes to Firefox have changed these files may . So, to follow along on your computer, download the correct revision of the source:# hg clone http://hg.mozilla.org/mozilla-central/# hg update f4800de50e03 #* (If you have changed.trouble building, as per {{bug|478871}}, try 4aed53dcf692 instead) <br>