diff --git a/ext/js/data/json-schema.js b/ext/js/data/json-schema.js
index 7b6b9c53..6a590911 100644
--- a/ext/js/data/json-schema.js
+++ b/ext/js/data/json-schema.js
@@ -103,8 +103,12 @@ class JsonSchemaProxyHandler {
     }
 
     deleteProperty(target, property) {
-        const required = this._schema.required;
-        if (Array.isArray(required) && required.includes(property)) {
+        const required = (
+            (typeof target === 'object' && target !== null) ?
+            (Array.isArray(target) || this._jsonSchemaValidator.isObjectPropertyRequired(this._schema, property)) :
+            true
+        );
+        if (required) {
             throw new Error(`${property} cannot be deleted`);
         }
         return Reflect.deleteProperty(target, property);
@@ -159,6 +163,11 @@ class JsonSchemaValidator {
         this._regexCache.clear();
     }
 
+    isObjectPropertyRequired(schema, property) {
+        const {required} = schema;
+        return Array.isArray(required) && required.includes(property);
+    }
+
     // Private
 
     _getPropertySchema(schema, property, value, path) {
diff --git a/test/test-schema.js b/test/test-json-schema.js
similarity index 78%
rename from test/test-schema.js
rename to test/test-json-schema.js
index 7a1ea9bc..d8e351be 100644
--- a/test/test-schema.js
+++ b/test/test-json-schema.js
@@ -28,6 +28,19 @@ vm.execute([
 const JsonSchemaValidator = vm.get('JsonSchemaValidator');
 
 
+function schemaValidate(schema, value) {
+    return new JsonSchemaValidator().isValid(value, schema);
+}
+
+function getValidValueOrDefault(schema, value) {
+    return new JsonSchemaValidator().getValidValueOrDefault(schema, value);
+}
+
+function createProxy(schema, value) {
+    return new JsonSchemaValidator().createProxy(value, schema);
+}
+
+
 function testValidate1() {
     const schema = {
         allOf: [
@@ -54,10 +67,6 @@ function testValidate1() {
         ]
     };
 
-    const schemaValidate = (value) => {
-        return new JsonSchemaValidator().isValid(value, schema);
-    };
-
     const jsValidate = (value) => {
         return (
             typeof value === 'number' &&
@@ -77,7 +86,7 @@ function testValidate1() {
     };
 
     for (let i = -111; i <= 111; i++) {
-        const actual = schemaValidate(i, schema);
+        const actual = schemaValidate(schema, i);
         const expected = jsValidate(i);
         assert.strictEqual(actual, expected);
     }
@@ -403,13 +412,9 @@ function testValidate2() {
         }
     ];
 
-    const schemaValidate = (value, schema) => {
-        return new JsonSchemaValidator().isValid(value, schema);
-    };
-
     for (const {schema, inputs} of data) {
         for (const {expected, value} of inputs) {
-            const actual = schemaValidate(value, schema);
+            const actual = schemaValidate(schema, value);
             assert.strictEqual(actual, expected);
         }
     }
@@ -686,17 +691,132 @@ function testGetValidValueOrDefault1() {
 
     for (const {schema, inputs} of data) {
         for (const [value, expected] of inputs) {
-            const actual = new JsonSchemaValidator().getValidValueOrDefault(schema, value);
+            const actual = getValidValueOrDefault(schema, value);
             vm.assert.deepStrictEqual(actual, expected);
         }
     }
 }
 
 
+function testProxy1() {
+    const data = [
+        // Object tests
+        {
+            schema: {
+                type: 'object',
+                required: ['test'],
+                additionalProperties: false,
+                properties: {
+                    test: {
+                        type: 'string',
+                        default: 'default'
+                    }
+                }
+            },
+            tests: [
+                {error: false, value: {test: 'default'}, action: (value) => { value.test = 'string'; }},
+                {error: true,  value: {test: 'default'}, action: (value) => { value.test = null; }},
+                {error: true,  value: {test: 'default'}, action: (value) => { delete value.test; }},
+                {error: true,  value: {test: 'default'}, action: (value) => { value.test2 = 'string'; }},
+                {error: false, value: {test: 'default'}, action: (value) => { delete value.test2; }}
+            ]
+        },
+        {
+            schema: {
+                type: 'object',
+                required: ['test'],
+                additionalProperties: true,
+                properties: {
+                    test: {
+                        type: 'string',
+                        default: 'default'
+                    }
+                }
+            },
+            tests: [
+                {error: false, value: {test: 'default'}, action: (value) => { value.test = 'string'; }},
+                {error: true,  value: {test: 'default'}, action: (value) => { value.test = null; }},
+                {error: true,  value: {test: 'default'}, action: (value) => { delete value.test; }},
+                {error: false, value: {test: 'default'}, action: (value) => { value.test2 = 'string'; }},
+                {error: false, value: {test: 'default'}, action: (value) => { delete value.test2; }}
+            ]
+        },
+        {
+            schema: {
+                type: 'object',
+                required: ['test1'],
+                additionalProperties: false,
+                properties: {
+                    test1: {
+                        type: 'object',
+                        required: ['test2'],
+                        additionalProperties: false,
+                        properties: {
+                            test2: {
+                                type: 'object',
+                                required: ['test3'],
+                                additionalProperties: false,
+                                properties: {
+                                    test3: {
+                                        type: 'string',
+                                        default: 'default'
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            },
+            tests: [
+                {error: false, action: (value) => { value.test1.test2.test3 = 'string'; }},
+                {error: true,  action: (value) => { value.test1.test2.test3 = null; }},
+                {error: true,  action: (value) => { delete value.test1.test2.test3; }},
+                {error: true,  action: (value) => { value.test1.test2 = null; }},
+                {error: true,  action: (value) => { value.test1 = null; }},
+                {error: true,  action: (value) => { value.test4 = 'string'; }},
+                {error: false, action: (value) => { delete value.test4; }}
+            ]
+        },
+
+        // Array tests
+        {
+            schema: {
+                type: 'array',
+                items: {
+                    type: 'string',
+                    default: 'default'
+                }
+            },
+            tests: [
+                {error: false, value: ['default'], action: (value) => { value[0] = 'string'; }},
+                {error: true,  value: ['default'], action: (value) => { value[0] = null; }},
+                {error: true,  value: ['default'], action: (value) => { delete value[0]; }},
+                {error: false, value: ['default'], action: (value) => { value[1] = 'string'; }}
+            ]
+        }
+    ];
+
+    for (const {schema, tests} of data) {
+        for (let {error, value, action} of tests) {
+            if (typeof value === 'undefined') { value = getValidValueOrDefault(schema, void 0); }
+            assert.ok(schemaValidate(schema, value));
+            console.log(error, value, schema);
+            const valueProxy = createProxy(schema, value);
+            if (error) {
+                assert.throws(() => action(valueProxy));
+            } else {
+                assert.doesNotThrow(() => action(valueProxy));
+            }
+        }
+    }
+}
+
+
 function main() {
     testValidate1();
     testValidate2();
     testGetValidValueOrDefault1();
+    testProxy1();
 }