@Override
	protected String getVertexId(Address address) {
		if (graphType != CONTROL_FLOW_GRAPH) {
			return null;
		}
		List<PcodeBlockBasic> blocks = hfunction.getBasicBlocks();
		for (PcodeBlockBasic block : blocks) {
			Address start = block.getStart();
			Address stop = block.getStop();
			if (address.compareTo(start) >= 0 && address.compareTo(stop) <= 0) {
				return Integer.toString(block.getIndex());
			}
		}
		return super.getVertexId(address);
	}
Listener for when an AST graph's nodes are selected.
Ghidra/Features/Decompiler/src/main/java/ghidra/app/plugin/core/decompile/actions/PCodeCfgDisplayListener.java