int getLeadingTabIndex() {
      try {
        final Field tabScrollerField = BasicTabbedPaneUI.class.getDeclaredField(TAB_SCROLLER_NAME);
        tabScrollerField.setAccessible(true);
        final Object tabScrollerValue = tabScrollerField.get(myUI);

        final Field leadingTabIndexField = tabScrollerValue.getClass().getDeclaredField(LEADING_TAB_INDEX_NAME);
        leadingTabIndexField.setAccessible(true);
        return leadingTabIndexField.getInt(tabScrollerValue);
      }
      catch (Exception exc) {
        final String writer = StringUtil.getThrowableText(exc);
        throw new IllegalStateException("myUI=" + myUI + "; cause=" + writer);
      }
    }
int getLeadingTabIndex()