/**
* Add new external resource, with no bindings
*
*/
private void handleAdd() {
AddExternalResourceDialog dialog = new AddExternalResourceDialog(this);
if (dialog.open() == Window.CANCEL)
return;
ExternalResourceDescription xrd = new ExternalResourceDescription_impl();
TreeItem item = new TreeItem(tree, SWT.NONE);
alterExistingXRD(dialog, xrd, item);
getResourceManagerConfiguration().addExternalResource(xrd);