@Override
	public String getTextSelection() {

		FGData currentData = controller.getFunctionGraphData();
		if (!currentData.hasResults()) {
			return null;
		}

		FGVertex focusedVertex = controller.getFocusedVertex();
		if (focusedVertex == null) {
			return null;
		}

		return focusedVertex.getTextSelection();
	}
Returns true when something destructive has happened to the data upon which the graph has
created, like a memory block move.
Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/FGProvider.java