docs: String getDiffOnlyButtonsHtml() {
  
          StringBuffer result = new StringBuffer();
          if (!getOriginalSource().equals(getCopySource())) {
              String onClick1 = "javascript:document.forms['diff-form'].mode.value = '";
              String onClick2 = "javascript:document.forms['diff-form'].mode.value = '";
              onClick1 += CmsDiffViewMode.ALL;
              onClick2 += CmsDiffViewMode.DIFF_ONLY;
              onClick1 += "'; document.forms['diff-form'].submit();";
              onClick2 += "'; document.forms['diff-form'].submit();";
              result.append(
                  getTwoButtonsHtml(
                      CmsDiffViewMode.DIFF_ONLY.getName().key(getLocale()),
                      CmsDiffViewMode.ALL.getName().key(getLocale()),
                      onClick1,
                      onClick2,
                      getMode() == CmsDiffViewMode.DIFF_ONLY));
          } else {
              // display all text, if there are no differences
              setMode(CmsDiffViewMode.ALL);
          }
          return result.toString();
      }