diff --git a/rhino/src/main/java/org/mozilla/javascript/ScriptRuntime.java b/rhino/src/main/java/org/mozilla/javascript/ScriptRuntime.java
index 27e2c188d4..aad5f3f51f 100644
--- a/rhino/src/main/java/org/mozilla/javascript/ScriptRuntime.java
+++ b/rhino/src/main/java/org/mozilla/javascript/ScriptRuntime.java
@@ -150,15 +150,11 @@ public static ScriptableObject initSafeStandardObjects(
         scope.associateValue(LIBRARY_SCOPE_KEY, scope);
         new ClassCache().associate(scope);
 
-        BaseFunction.init(cx, scope, sealed);
         NativeObject.init(scope, sealed);
+        BaseFunction.init(cx, scope, sealed);
 
         Scriptable objectProto = ScriptableObject.getObjectPrototype(scope);
 
-        // Function.prototype.__proto__ should be Object.prototype
-        Scriptable functionProto = ScriptableObject.getClassPrototype(scope, "Function");
-        functionProto.setPrototype(objectProto);
-
         // Set the prototype of the object passed in if need be
         if (scope.getPrototype() == null) scope.setPrototype(objectProto);
 
diff --git a/rhino/src/main/java/org/mozilla/javascript/ScriptableObject.java b/rhino/src/main/java/org/mozilla/javascript/ScriptableObject.java
index ed72aa6cfd..436cbab2d1 100644
--- a/rhino/src/main/java/org/mozilla/javascript/ScriptableObject.java
+++ b/rhino/src/main/java/org/mozilla/javascript/ScriptableObject.java
@@ -710,6 +710,7 @@ public Scriptable getPrototype() {
     /** Sets the prototype of the object. */
     @Override
     public void setPrototype(Scriptable m) {
+        checkNotSealed("__proto__", 0);
         prototypeObject = m;
     }
 
@@ -722,6 +723,7 @@ public Scriptable getParentScope() {
     /** Sets the parent (enclosing) scope of the object. */
     @Override
     public void setParentScope(Scriptable m) {
+        checkNotSealed("__parent__", 0);
         parentScopeObject = m;
     }
 
diff --git a/tests/src/test/java/org/mozilla/javascript/tests/SealedSharedScopeTest.java b/tests/src/test/java/org/mozilla/javascript/tests/SealedSharedScopeTest.java
index d801bf130e..9c8b10399c 100644
--- a/tests/src/test/java/org/mozilla/javascript/tests/SealedSharedScopeTest.java
+++ b/tests/src/test/java/org/mozilla/javascript/tests/SealedSharedScopeTest.java
@@ -22,6 +22,7 @@
 import org.mozilla.javascript.IdFunctionObject;
 import org.mozilla.javascript.ImporterTopLevel;
 import org.mozilla.javascript.Scriptable;
+import org.mozilla.javascript.ScriptableObject;
 import org.mozilla.javascript.Wrapper;
 
 @RunWith(BlockJUnit4ClassRunner.class)
@@ -36,6 +37,19 @@ public class SealedSharedScopeTest {
     public void setUp() throws Exception {
         try (Context tmpCtx = Context.enter()) {
             sharedScope = new ImporterTopLevel(tmpCtx, true);
+            tmpCtx.evaluateString(
+                    sharedScope,
+                    "jsObj = {'bar': 42};\n"
+                    // Some tests...
+                    // + "Object.defineProperties(jsObj, { baz : { writable: true, value: 'aaa'
+                    // }});\n"
+                    // + "Object.seal(jsObj);"
+                    ,
+                    "init",
+                    1,
+                    null);
+            // Note: Object.seal != ScriptableObject.sealObject
+            ((ScriptableObject) sharedScope.get("jsObj", sharedScope)).sealObject();
             sharedScope.sealObject();
         }
 
@@ -177,4 +191,56 @@ public void importClassSucceedsOnScope() throws Exception {
             assertEquals("ReferenceError: \"Locale\" is not defined. (test#1)", e.getMessage());
         }
     }
+
+    @Test
+    public void testSealedJsModifyProp() {
+        String s = evaluateString(scope1, "jsObj").toString();
+        assertEquals("[object Object]", s);
+
+        try {
+            evaluateString(scope1, "'use strict';jsObj.bar = 3");
+            fail("EvaluatorException expected");
+        } catch (EvaluatorException e) {
+            assertEquals(
+                    "Cannot modify a property of a sealed object: bar. (test#1)", e.getMessage());
+        }
+    }
+
+    @Test
+    public void testSealedJsAddProp() {
+        String s = evaluateString(scope1, "jsObj").toString();
+        assertEquals("[object Object]", s);
+
+        try {
+            evaluateString(scope1, "'use strict';jsObj.foo = 3");
+            fail("EvaluatorException expected");
+        } catch (EvaluatorException e) {
+            assertEquals(
+                    "Cannot modify a property of a sealed object: foo. (test#1)", e.getMessage());
+        }
+    }
+
+    @Test
+    public void testSealedJsModifyProto() {
+        try {
+            evaluateString(scope1, "jsObj.__proto__ = {}");
+            fail("EvaluatorException expected");
+        } catch (EvaluatorException e) {
+            assertEquals(
+                    "Cannot modify a property of a sealed object: __proto__. (test#1)",
+                    e.getMessage());
+        }
+    }
+
+    @Test
+    public void testSealedJsModifyParent() {
+        try {
+            evaluateString(scope1, "jsObj.__parent__ = {}");
+            fail("EvaluatorException expected");
+        } catch (EvaluatorException e) {
+            assertEquals(
+                    "Cannot modify a property of a sealed object: __parent__. (test#1)",
+                    e.getMessage());
+        }
+    }
 }