code: public DCPanel createPanel() {
          final DCPanel parentPanel = new DCPanel();
          parentPanel.setLayout(new BorderLayout());
          parentPanel.add(_sourceComboBoxPanel, BorderLayout.CENTER);
          parentPanel.add(_buttonPanel, BorderLayout.EAST);
          return parentPanel;
      }
docs: Creates a panel containing ButtonPanel and SourceComboboxPanel
  
  @return DCPanel