What is the purpose of the HTML Code tab in the Canvas?

When you select a template, edit text, insert an image or make any other changes using any of our editors, HTML code (used to construct your email) is generated behind the scenes. Clicking the HTML Code tab in the Canvas editor will let you view and make changes to this code directly. You should only make changes to the source code if you are comfortable working with HTML. Changes you make to the source code will affect the layout of your mail message.
 
You may also find that some changes you make in the source code are altered or ignored when you switch back to  Graphical Editor. For example if you leave a blank space in a table cell in the source code, switch to Graphical Editor and then back to HTML Code you will see the space encoded as  . The graphical and source editors work hand in hand to build your email message and changes made to the source could be overwritten by the graphical editor.