jQuery(document).on('tinymce-editor-setup', function( event, editor ) { editor.settings.toolbar1 += ',mybutton'; editor.addButton( 'mybutton', { text: 'Countdowns', icon: false, onclick: function () { jQuery('#ycd-dialog').dialog({ width: 450, modal: true, title: "Insert the shortcode", dialogClass: "ycd-countdown-builder" }); } }); });