code: function buildDropdown(trumbowyg) {
          var dropdown = [];
  
          $.each(trumbowyg.o.plugins.lineheight.sizeList, function(index, size) {
              trumbowyg.addBtnDef('lineheight_' + size, {
                  text: trumbowyg.lang.lineheights[size] || size,
                  hasIcon: false,
                  fn: function(){
                      trumbowyg.saveRange();
                      var text = trumbowyg.getRangeText();
                      if (text.replace(/\s/g, '') !== '') {
                          try {
                              var parent = getSelectionParentElement();
                              $(parent).css('lineHeight', size);
                          } catch (e) {
                          }
                      }
                  }
              });
              dropdown.push('lineheight_' + size);
          });
  
          return dropdown;
      }
docs: Build the dropdown