Chapter 15: Page 301 - 'A Complex Action Button'
At the top of page 301, there is a code block that includes the UI definition, standard in any XML file. Unfortunately a line was cut off at the end of this block which begins the definition of the button in question. That block of code should read as follows:
<Ui xmlns="http://www.blizzard.com/wow/ui/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.blizzard.com/wow/ui/
..\FrameXML\UI.xsd">
<Button name="QuickCasterButton" inherits="ActionButtonTemplate,SecureActionButtonTemplate">