Add ‘code’ button to teeny_mce visual editor

I’m using the following php to attempt to add a ‘code’ formatting button to the teeny mce editor (I’d like to keep it teeny if possible):

function fx_teeny_mce_buttons( $buttons, $editor_id ) {
	$buttons[] = 'code';
	return $buttons;
}
add_filter( 'bbp_get_teeny_mce_buttons', 'fx_teeny_mce_buttons');

However, the button isn’t showing. It does, however, appear in the $buttons array.

Any suggestions?