private void createAndDisplaySubGraph() {
		GraphDisplay display = graphDisplayProvider.getGraphDisplay(false, TaskMonitor.DUMMY);
		try {
			display.setGraph(createSubGraph(), graphRenderer.getGraphDisplayOptions(),
				title + " - Sub-graph", false, TaskMonitor.DUMMY);
			display.setGraphDisplayListener(listener.cloneWith(display));
			copyActionsToNewGraph(display);
		}
		catch (CancelledException e) {
			// using Dummy, so can't happen
		}
	}
Ungroup the selected vertices. If the focusedVertex is no longer in the graph, null it. This
will happen if the focusedVertex was the GroupVertex
Ghidra/Features/GraphServices/src/main/java/ghidra/graph/visualization/DefaultGraphDisplay.java