code: private void handleBrowse() {
  		ContainerSelectionDialog dialog = new ContainerSelectionDialog(
  				getShell(), ResourcesPlugin.getWorkspace().getRoot(), false,
  				"Select new file container");
  		if (dialog.open() == ContainerSelectionDialog.OK) {
  			Object[] result = dialog.getResult();
  			if (result.length == 1) {
  				projectText.setText(((Path) result[0]).toString());
  			}
  		}
  	}
docs: Uses the standard container selection dialog to choose the new value for
  the container field.