Jamie

Excellent – thank you!

Thanks, definitely will check on that. I thought the whole purpose of setting merge to true was to but it seems more complicated than that. Super awesome of you to help figure out this issue 🙂

Hi Josh! Thanks for responding. I followed a tutorial on this and this is the code I’m using

function my_mce_before_init_insert_formats( $init_array ) {  

// Define the style_formats array

	$style_formats = array(
		// Each array child is a format with it's own settings
		array(
			'title' => 'Content Block',
			'block' => 'span',
			'classes' => 'content-block',
			'wrapper' => true,

		),
		array(
			'title' => 'Blue Button',
			'block' => 'span',
			'classes' => 'blue-button',
			'wrapper' => true,
		),
		array(
			'title' => 'Red Button',
			'block' => 'span',
			'classes' => 'red-button',
			'wrapper' => true,
		),
	);
	// Insert the array, JSON ENCODED, into 'style_formats'
	$init_array['style_formats_merge'] = true;
	$init_array['style_formats'] = json_encode( $style_formats );

	return $init_array;  

}
// Attach callback to 'tiny_mce_before_init'
add_filter( 'tiny_mce_before_init', 'my_mce_before_init_insert_formats' );

Following this tutorial here: http://www.wpbeginner.com/wp-tutorials/how-to-add-custom-styles-to-wordpress-visual-editor/

Things to note:
I’ve moved the merge code to different locations to see if that made a difference. I tried it after the $init_array['style_formats'] = json_encode( $style_formats ); line as well as before $style_formats = array(