Formatting admin pages using meta boxes
As a plugin's administration page becomes longer and more complex, it becomes important to divide its content into multiple sections. While standard HTML headers or fieldset tags could be used for this task, they lack the usefulness and nice visual appearance of meta boxes. Meta boxes are the containers that show up in many WordPress content editors, as well as on the main administration Dashboard page.
Beyond visually organizing content, meta boxes are very powerful, since they allow site administrators to collapse configuration sections that they don't use, reorder sections based on their needs, and even hide elements that they don't want to see.
Getting ready
You should have already followed the Accessing user settings from action and filter hooks recipe. Alternatively, you can get the resulting code (ch3/ch2-page-header-output/ch2-page-header-output-v9.php) from the book's GitHub page. You should rename the ch2...
