Mouse turns to 'X' with sidebar

I want to trigger the mouse to change from pointer to X on click like here: http://themes.semicolonweb.com/html/canvas/side-panel-light.php#

Is it via CSS or javascript/jquery?

How do I enable it with another header.. What elements are required?

Nevermind

try this css:

cursor: url(images/my-cursor.png), auto;