Apply custom style to single word in WordPress
Solved it… In my functions.php I should have put: array( ‘title’ => ‘Hidden Element’, ‘inline’ => ‘span’, ‘classes’ => ‘hiddenElement’, ‘wrapper’ => false, ), not array( ‘title’ => ‘Hidden Element’, ‘block’ => ‘span’, ‘classes’ => ‘hiddenElement’, ‘wrapper’ => false, ), as here: http://www.wpbeginner.com/wp-tutorials/how-to-add-custom-styles-to-wordpress-visual-editor/