code: function (btnName) {
              var t = this,
                  prefix = t.o.prefix,
                  btn = t.btnsDef[btnName],
                  hasIcon = btn.hasIcon != null ? btn.hasIcon : true;
  
              if (btn.key) {
                  t.keys[btn.key] = {
                      fn: btn.fn || btnName,
                      param: btn.param || btnName
                  };
              }
  
              t.tagToButton[(btn.tag || btnName).toLowerCase()] = btnName;
  
              return $('<button/>', {
                  type: 'button',
                  class: prefix + btnName + '-dropdown-button ' + (btn.class || '') + (btn.ico ? ' ' + prefix + btn.ico + '-button' : ''),
                  html: t.hasSvg && hasIcon ?
                    '<svg><use xlink:href="' + t.svgPath + '#' + prefix + (btn.ico || btnName).replace(/([A-Z]+)/g, '-$1').toLowerCase() + '"/></svg>' + (btn.text || btn.title || t.lang[btnName] || btnName) :
                    (btn.text || btn.title || t.lang[btnName] || btnName),
                  title: (btn.key ? '(' + (t.isMac ? 'Cmd' : 'Ctrl') + ' + ' + btn.key + ')' : null),
                  style: btn.style || null,
                  mousedown: function () {
                      $('body', t.doc).trigger('mousedown');
  
                      t.execCmd(btn.fn || btnName, btn.param || btnName, btn.forceCss);
  
                      return false;
                  }
              });
          }
docs: Build a button for dropdown menu @param n : name of the subbutton