docs: private JButton getSelectButton() {
  		if (selectButton == null) {
  			selectButton = new JButton();
  			selectButton.setText(Constant.messages.getString("siteselect.button.select"));
  			selectButton.setEnabled(false);	// Enabled when a node is selected
  			selectButton.addActionListener(new java.awt.event.ActionListener() { 
  				@Override
  				public void actionPerformed(java.awt.event.ActionEvent e) {
  					if (treeSite.getLastSelectedPathComponent() != null) {
  						nodeSelected();
  					} else if (treeContext.getLastSelectedPathComponent() != null) {
  						contextSelected();
  					}
  				}
  			});
  
  		}
  		return selectButton;
  	}