I'm trying to preload some libraries into a global scope (things like chai.js). This changes the prototype of some objects and I realised that this works for ENGINE\_SCOPE but not for GLOBAL\_SCOPE. 

Minimal example:

```
ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
Bindings globalBindings = engine.createBindings();
engine.eval("Object.prototype.test = function(arg){print(arg);}", globalBindings);

//works as expected, printing "hello"
engine.getContext().setBindings(globalBindings, ScriptContext.ENGINE_SCOPE);
engine.eval("var x = {}; x.test('hello');");

//throws TypeError: null is not a function in <eval> at line number 1
engine.getContext().setBindings(engine.createBindings(), ScriptContext.ENGINE_SCOPE);
engine.getContext().setBindings(globalBindings, ScriptContext.GLOBAL_SCOPE);
engine.eval("var x = {}; x.test('hello');");

```

Is there a workaround to make it work as expected, i.e. changes are propagated correctly from global to engine scope?