There is source code in the plugin to auto-expand when hovered over but it’s commented out. You must edit three files:
In method enqueueScripts(), uncomment the line invoking wp_enqueue_script() so wp-syntax.js will be loaded.
overflow-yproperties of class
.wp_syntaxare set to
box-shadowCSS property added during the mouseover event because that design approach is now considered archaic.
The mouseover/mouseout events for expand/collapse of the code block will be immediate with no animated delay. If you wish to fancy it up like Four Kitchens’ blog, look into adding the CSS3 transition property to class