How to create a categories widget like this

The blog you’re referencing uses the following CSS to show the crosses:

#mycategoryorder-3 ul li {
background: url(“images/bullet.gif”) no-repeat scroll 5px 4px transparent;
clear: both;
padding-bottom: 10px;
padding-left: 16px;

So as you can see the cross is a simple GIF image.

Also, add the following CSS to your stylesheet:

#mycategoryorder-3 ul {
list-style-type: none;
}

this would be the css of the plugin, or theme?

In your theme’s style.css file. You can access this under Appearance > Editor >> style.css.

thank you!

You’re welcome!