Added the styleselect shortcode to the plugin Toolbar 2 and the Styles dropdown shows but no styles present.
styleselect ? Goes in the comma delimited list of codes in the toolbars? Others in the “Additionally Available” list work.
styleselect? wow, never heard of that… but after looking, you are right its in the admin help… but not sure if its still valid or not… that list ‘might’ be from a while back when we had our own tinymce version in the plugin… not too long ago we switched to using the built in wp editor for tinymce…and just not sure that is valid…
I ran a quick text on my local test site and surprisingly, I got three styles listed: sfcode, syntax and sfcodeselect
but not really sure where they came from or why… or what would make them show or not show…
might be skin dependent too? which one do you use? also, maybe it will help, but what were you expecting to be shown there? 
I am going to have to open a ticket for some research… My instinct says the list is outdated since the switch to wp editor, but I do not know that… we either need to make sure what is listed works or list the ones the wp editor supports…
Andy, do you know off the top of your head?