/**
   * DOCUMENT ME!
   *
   * @param evt DOCUMENT ME!
   */
  private void btnThisMonthActionPerformed(final java.awt.event.ActionEvent evt) {
    final Calendar calendar = Calendar.getInstance();

    final Date toDate = calendar.getTime();

    calendar.set(Calendar.DAY_OF_MONTH, 1);
    final Date fromDate = calendar.getTime();

    try {
      lockDateButtons = true;
      dpiFrom.setDate(fromDate);
      dpiTo.setDate(toDate);
    } finally {
      lockDateButtons = false;
    }

    periodChanged();
    refreshFortfuehrungsList();
  }