code: protected ILaunchConfiguration chooseConfiguration(
  			List<ILaunchConfiguration> configList)
  	{
  		IDebugModelPresentation labelProvider = DebugUITools.newDebugModelPresentation();
  		ElementListSelectionDialog dialog = new ElementListSelectionDialog(getShell(), labelProvider);
  		dialog.setElements(configList.toArray());
  		dialog.setTitle(getTypeSelectionTitle());
  		dialog.setMessage(LauncherMessages.VdmLaunchShortcut_2);
  		dialog.setMultipleSelection(false);
  		int result = dialog.open();
  		labelProvider.dispose();
  		if (result == Window.OK)
  		{
  			return (ILaunchConfiguration) dialog.getFirstResult();
  		}
  		return null;
  	}
docs: Returns a configuration from the given collection of configurations that should be launched, or <code>null</code>
  to cancel. Default implementation opens a selection dialog that allows the user to choose one of the specified
  launch configurations. Returns the chosen configuration, or <code>null</code> if the user cancels.
  
  @param configList
  list of configurations to choose from
  @return configuration to launch or <code>null</code> to cancel