dialog.show();
dialog.setVisible(true);
    private void aboutItemActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_aboutItemActionPerformed        AboutDialog dialog = new AboutDialog(this, true);        dialog.setSize(500, 354);        dialog.setLocationRelativeTo(null); // center the dialog        dialog.show();    }//GEN-LAST:event_aboutItemActionPerformed