* Invoked as part from the boilerplate install block. This installs the
* listeners from BasicGraphUI in the graph.
*/
protected void installListeners() {
// Install Local Handlers
TransferHandler th = graph.getTransferHandler();
if (th == null || th instanceof UIResource) {
defaultTransferHandler = createTransferHandler();
// Not supported in headless environment
try {
graph.setTransferHandler(defaultTransferHandler);