@Override
	ProgramSelection getProgramSelection() {
		AddressSet addresses = new AddressSet();
		Set<FGVertex> vertices = groupVertex.getVertices();
		for (FGVertex v : vertices) {
			ProgramSelection programSelection = v.getProgramSelection();
			if (programSelection == null) {
				continue;
			}
			addresses.add(programSelection);
		}

		return new ProgramSelection(addresses);
	}
A bit of a hack that triggers the text area to update its preferred height now before we
render so that it doesn't change later.
Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/graph/vertex/GroupedFunctionGraphComponentPanel.java