public void setOperandLabel(ListingActionContext context) {
		programActionContext = context;
		setStatusText("");
		myChoice.clearModel();

		Symbol s = getSymbol(context);
		Symbol[] symbols = context.getProgram().getSymbolTable().getSymbols(s.getAddress());
		for (Symbol symbol : symbols) {
			myChoice.addToModel(symbol.getName(true));
		}
		setTitle("Set Label at " + s.getAddress());
		myChoice.setSelectedItem(s.getName(true));
		PluginTool tool = plugin.getTool();
		tool.showDialog(this);
	}
This method gets called when the user clicks on the Cancel Button.  The base
class calls this method.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/label/OperandLabelDialog.java