private final NodeBoxDocument document;
public PortPane(NodeBoxDocument document) {
this.document = document;
setLayout(new BorderLayout());
paneHeader = new PaneHeader("Ports");
NButton metadataButton = new NButton("Metadata", getClass().getResourceAsStream("/port-metadata.png"));
metadataButton.setActionMethod(this, "editMetadata");
paneHeader.add(metadataButton);
portView = new PortView(this, document);
add(paneHeader, BorderLayout.NORTH);