Check out this example on tinymce. By examining the configuration, you will see the specified setting (style_formats)
// Style formats
style_formats : [
{title : 'Bold text', inline : 'b'},
{title : 'Red text', inline : 'span', styles : {color : '#ff0000'}},
{title : 'Red header', block : 'h1', styles : {color : '#ff0000'}},
{title : 'Example 1', inline : 'span', classes : 'example1'},
{title : 'Example 2', inline : 'span', classes : 'example2'},
{title : 'Table styles'},
{title : 'Table row 1', selector : 'tr', classes : 'tablerow1'}
],
With this tinymce configuration setting, you can specify which styles are visible in the style dropdown list and the css field of the link popup.
Update: Unfortunately, the above does not affect the class dropdown in the popup.
Here is the correct way to configure the setting for examples:
advlink_styles: 'Code=code;Excel=excel;Flash=flash;Sound=sound;'
You are already using the advlink plugin, so feel free to implement this configuration setting. See how it works!