diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0718c829..ad2c9cff 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+# 5.8.0 (next)
+
+- `set()` method will increase `changed` prop and trigger `onChange` Event Hook
+- Mobx events (observe/intercept) allowed props guarded.
+- Introduced `onSync` Hook (triggered on `onChange` Event Handler)
+- Introduced `validateOnSubmit` form option (active by default).
+- Fix: `ref` prop for separated props mode renamed to `refs` (plural)
+- Fix: #337
 # 5.7.1 (next)
 
 - fix: allow `ref` prop on `set()`
diff --git a/src/Base.ts b/src/Base.ts
index f41e8fa2..7cf66a36 100755
--- a/src/Base.ts
+++ b/src/Base.ts
@@ -16,7 +16,7 @@ import FieldInterface from "./models/FieldInterface";
 import {
   props,
   allowedProps,
-  checkPropType,
+  checkPropOccurrence,
   throwError,
   isArrayOfObjects,
   getObservableMapValues,
@@ -37,8 +37,9 @@ import {
   pathToFieldsTree,
   defaultClearValue,
 } from "./parser";
-import { FieldPropsEnum } from "./models/FieldProps";
+import { AllowedFieldPropsTypes, FieldPropsEnum, SeparatedPropsMode } from "./models/FieldProps";
 import { OptionsEnum } from "./models/OptionsModel";
+import { ValidationHooks } from "./models/ValidatorInterface";
 export default class Base implements BaseInterface {
   noop = () => {};
 
@@ -258,29 +259,29 @@ export default class Base implements BaseInterface {
     };
 
     const props = {
-      $value: _.get(initial["values"], path),
-      $label: _try("labels"),
-      $placeholder: _try("placeholders"),
-      $default: _try("defaults"),
-      $initial: _try("initials"),
-      $disabled: _try("disabled"),
-      $deleted: _try("deleted"),
-      $type: _try("types"),
-      $related: _try("related"),
-      $rules: _try("rules"),
-      $options: _try("options"),
-      $bindings: _try("bindings"),
-      $extra: _try("extra"),
-      $hooks: _try("hooks"),
-      $handlers: _try("handlers"),
-      $validatedWith: _try("validatedWith"),
-      $validators: _try("validators"),
-      $observers: _try("observers"),
-      $interceptors: _try("interceptors"),
-      $input: _try("input"),
-      $output: _try("output"),
-      $autoFocus: _try("autoFocus"),
-      $ref: _try("ref"),
+      $value: _.get(initial[SeparatedPropsMode.values], path),
+      $label: _try(SeparatedPropsMode.labels),
+      $placeholder: _try(SeparatedPropsMode.placeholders),
+      $default: _try(SeparatedPropsMode.defaults),
+      $initial: _try(SeparatedPropsMode.initials),
+      $disabled: _try(SeparatedPropsMode.disabled),
+      $deleted: _try(SeparatedPropsMode.deleted),
+      $type: _try(SeparatedPropsMode.types),
+      $related: _try(SeparatedPropsMode.related),
+      $rules: _try(SeparatedPropsMode.rules),
+      $options: _try(SeparatedPropsMode.options),
+      $bindings: _try(SeparatedPropsMode.bindings),
+      $extra: _try(SeparatedPropsMode.extra),
+      $hooks: _try(SeparatedPropsMode.hooks),
+      $handlers: _try(SeparatedPropsMode.handlers),
+      $validatedWith: _try(SeparatedPropsMode.validatedWith),
+      $validators: _try(SeparatedPropsMode.validators),
+      $observers: _try(SeparatedPropsMode.observers),
+      $interceptors: _try(SeparatedPropsMode.interceptors),
+      $input: _try(SeparatedPropsMode.input),
+      $output: _try(SeparatedPropsMode.output),
+      $autoFocus: _try(SeparatedPropsMode.autoFocus),
+      $ref: _try(SeparatedPropsMode.refs),
     };
 
     const field = this.state.form.makeField({
@@ -314,8 +315,16 @@ export default class Base implements BaseInterface {
     this.$submitting = true;
     this.$submitted += 1;
 
-    const exec = (isValid: boolean) =>
-      isValid ? this.execHook("onSuccess", o) : this.execHook("onError", o);
+    if (!this.state.options.get(OptionsEnum.validateOnSubmit, this)) {
+      return Promise
+        .resolve(this)
+        .then(action(() => (this.$submitting = false)))
+        .then(() => this);
+    }
+
+    const exec = (isValid: boolean) => isValid
+      ? this.execHook(ValidationHooks.onSuccess, o)
+      : this.execHook(ValidationHooks.onError, o);
 
     return (
       this.validate({
@@ -345,12 +354,12 @@ export default class Base implements BaseInterface {
     Check Field Computed Values
    */
   check(prop: string, deep: boolean = false): boolean {
-    allowedProps("computed", [prop]);
+    allowedProps(AllowedFieldPropsTypes.computed, [prop]);
 
     return deep
-      ? checkPropType({
-          type: props.types[prop],
-          data: this.deepCheck(props.types[prop], prop, this.fields),
+      ? checkPropOccurrence({
+          type: props.occurrences[prop],
+          data: this.deepCheck(props.occurrences[prop], prop, this.fields),
         })
       : (this as any)[prop];
   }
@@ -365,7 +374,7 @@ export default class Base implements BaseInterface {
         }
 
         const $deep = this.deepCheck(type, prop, field.fields);
-        check.push(checkPropType({ type, data: $deep }));
+        check.push(checkPropOccurrence({ type, data: $deep }));
         return check;
       },
       []
@@ -458,7 +467,7 @@ export default class Base implements BaseInterface {
       );
     }
 
-    allowedProps("all", _.isArray(prop) ? prop : [prop]);
+    allowedProps(AllowedFieldPropsTypes.all, _.isArray(prop) ? prop : [prop]);
 
     if (_.isString(prop)) {
       if (strict && this.fields.size === 0) {
@@ -536,14 +545,16 @@ export default class Base implements BaseInterface {
   set(prop: any, data?: any): void {
     // UPDATE CUSTOM PROP
     if (_.isString(prop) && !_.isUndefined(data)) {
-      allowedProps("field", [prop]);
+      allowedProps(AllowedFieldPropsTypes.editable, [prop]);
       const deep = (_.isObject(data) && prop === FieldPropsEnum.value) || _.isPlainObject(data);
-      if (deep && this.hasNestedFields) this.deepSet(prop, data, "", true);
-      else _.set(this, `$${prop}`, data);
-
+      if (deep && this.hasNestedFields) return this.deepSet(prop, data, "", true);
+      // else _.set(this, `$${prop}`, data);
       if (prop === FieldPropsEnum.value) {
-        this.$changed ++;
-        this.state.form.$changed ++;
+        (this as any).value = parseInput((this as any).$input, {
+          separated: data,
+        });
+      } else {
+        _.set(this, `$${prop}`, data);
       }
       return;
     }
@@ -667,7 +678,15 @@ export default class Base implements BaseInterface {
   /**
     MobX Event (observe/intercept)
    */
-  MOBXEvent({ path = null, key = FieldPropsEnum.value, call, type }: any): void {
+  MOBXEvent({
+    prop = FieldPropsEnum.value,
+    key = null,
+    path = null,
+    call,
+    type
+  }: any): void {
+    let $prop = key || prop;
+    allowedProps(AllowedFieldPropsTypes.observable, [$prop]);
     const $instance = this.select(path || this.path, null, null) || this;
 
     const $call = (change: any) =>
@@ -685,23 +704,21 @@ export default class Base implements BaseInterface {
 
     if (type === "observer") {
       fn = observe;
-      ffn = (cb: any) => observe($instance.fields, cb);
+      ffn = (cb: any) => observe($instance.fields, cb); // fields
     }
 
     if (type === "interceptor") {
-      // eslint-disable-next-line
-      key = `$${key}`;
+      $prop = `$${prop}`;
       fn = intercept;
-      ffn = $instance.fields.intercept;
+      ffn = $instance.fields.intercept; // fields
     }
-
-    const $dkey = $instance.path ? `${key}@${$instance.path}` : key;
+    const $dkey = $instance.path ? `${$prop}@${$instance.path}` : $prop;
 
     _.merge(this.state.disposers[type], {
       [$dkey]:
-        key === FieldPropsEnum.fields
+      $prop === FieldPropsEnum.fields
           ? ffn.apply((change: any) => $call(change))
-          : (fn as any)($instance, key, (change: any) => $call(change)),
+          : (fn as any)($instance, $prop, (change: any) => $call(change)),
     });
   }
 
diff --git a/src/Field.ts b/src/Field.ts
index fddf8512..a6663565 100755
--- a/src/Field.ts
+++ b/src/Field.ts
@@ -120,6 +120,7 @@ export default class Field extends Base implements FieldInterface {
   disposeValidationOnChange: any;
 
   files: any;
+
   constructor({
     key,
     path,
@@ -225,9 +226,8 @@ export default class Field extends Base implements FieldInterface {
 
     this.execHook(FieldPropsEnum.onInit);
 
-    // handle Field onChange Hook for nested fields
-    this.hasNestedFields
-      && autorun(() => this.changed && this.execHook(FieldPropsEnum.onChange));
+    // handle Field onChange Hook
+    autorun(() => this.changed && this.execHook(FieldPropsEnum.onChange));
   }
 
   /* ------------------------------------------------------------------ */
@@ -436,10 +436,12 @@ export default class Field extends Base implements FieldInterface {
     this.value = e;
   });
 
-  onChange = (...args: any) =>
+  onSync = (...args: any) =>
     this.type === "file"
       ? this.onDrop(...args)
-      : this.execHandler(FieldPropsEnum.onChange, args, this.sync);
+      : this.execHandler(FieldPropsEnum.onSync, args, this.sync);
+
+  onChange = this.onSync;
 
   onToggle = (...args: any) =>
     this.execHandler(FieldPropsEnum.onToggle, args, this.sync);
diff --git a/src/Form.ts b/src/Form.ts
index 43e2c7c2..5168cc23 100755
--- a/src/Form.ts
+++ b/src/Form.ts
@@ -7,10 +7,7 @@ import State from "./State";
 import Field from "./Field";
 import ValidatorInterface from "./models/ValidatorInterface";
 import FieldInterface, { FieldConstructor } from "./models/FieldInterface";
-import FormInterface, {
-  FieldsDefinitions,
-  FormConfig,
-} from "./models/FormInterface";
+import FormInterface, { FieldsDefinitions, FormConfig } from "./models/FormInterface";
 import { FieldPropsEnum } from "./models/FieldProps";
 import { OptionsEnum } from "./models/OptionsModel";
 
@@ -166,7 +163,7 @@ export default class Form extends Base implements FormInterface {
     return new Field(data);
   }
 
-  /**
+  /** DEPRECATED
     Init Form Fields and Nested Fields
 
   init($fields: any = null): void {
diff --git a/src/Options.ts b/src/Options.ts
index c7be4baf..63572953 100644
--- a/src/Options.ts
+++ b/src/Options.ts
@@ -27,6 +27,7 @@ export default class Options implements OptionsInterface {
     showErrorsOnClear: false,
     showErrorsOnReset: true,
     validateOnInit: true,
+    validateOnSubmit: true,
     validateOnBlur: true,
     validateOnChange: false,
     validateOnChangeAfterInitialBlur: false,
diff --git a/src/models/FieldInterface.ts b/src/models/FieldInterface.ts
index 29584daa..29f0affe 100644
--- a/src/models/FieldInterface.ts
+++ b/src/models/FieldInterface.ts
@@ -44,6 +44,7 @@ export default interface FieldInterface extends BaseInterface {
   touched: boolean;
   deleted: boolean;
   // handlers
+  onSync(args: any): any;
   onChange(args: any): any;
   onToggle(args: any): any;
   onBlur(args: any): any;
diff --git a/src/models/FieldProps.ts b/src/models/FieldProps.ts
index 0e1f366b..e2d0e830 100644
--- a/src/models/FieldProps.ts
+++ b/src/models/FieldProps.ts
@@ -43,6 +43,7 @@ export enum FieldPropsEnum {
   hasError = "hasError",
   // handlers
   onInit = "onInit",
+  onSync = "onSync",
   onChange = "onChange",
   onBlur = "onBlur",
   onFocus = "onFocus",
@@ -61,3 +62,41 @@ export enum FieldPropsEnum {
 export type FieldPropsType = {
   [key in FieldPropsEnum]?: any;
 }
+
+export enum AllowedFieldPropsTypes {
+  computed = 'computed',
+  observable = 'observable',
+  editable = 'editable',
+  all = 'all',
+}
+
+export enum FieldPropsOccurrence {
+  some = 'some',
+  every = 'every',
+}
+
+export enum SeparatedPropsMode {
+  values = 'values',
+  labels = 'labels',
+  placeholders = 'placeholders',
+  defaults = 'defaults',
+  initials = 'initials',
+  disabled = 'disabled',
+  deleted = 'deleted',
+  types = 'types',
+  related = 'related',
+  rules = 'rules',
+  options = 'options',
+  bindings = 'bindings',
+  extra = 'extra',
+  hooks = 'hooks',
+  handlers = 'handlers',
+  validatedWith = 'validatedWith',
+  validators = 'validators',
+  observers = 'observers',
+  interceptors = 'interceptors',
+  input = 'input',
+  output = 'output',
+  autoFocus = 'autoFocus',
+  refs = 'refs',
+}
\ No newline at end of file
diff --git a/src/models/OptionsModel.ts b/src/models/OptionsModel.ts
index f2f91651..d5a197d7 100644
--- a/src/models/OptionsModel.ts
+++ b/src/models/OptionsModel.ts
@@ -10,6 +10,7 @@ export enum OptionsEnum {
   showErrorsOnClear = 'showErrorsOnClear',
   showErrorsOnReset = 'showErrorsOnReset',
   validateOnInit = 'validateOnInit',
+  validateOnSubmit = 'validateOnSubmit',
   validateOnBlur = 'validateOnBlur',
   validateOnChange = 'validateOnChange',
   validateOnChangeAfterInitialBlur = 'validateOnChangeAfterInitialBlur',
@@ -47,6 +48,7 @@ export default interface OptionsModel {
   [OptionsEnum.showErrorsOnClear]?: boolean;
   [OptionsEnum.showErrorsOnReset]?: boolean;
   [OptionsEnum.validateOnInit]?: boolean;
+  [OptionsEnum.validateOnSubmit]?: boolean;
   [OptionsEnum.validateOnBlur]?: boolean;
   [OptionsEnum.validateOnChange]?: boolean;
   [OptionsEnum.validateOnChangeAfterInitialBlur]?: boolean;
diff --git a/src/models/ValidatorInterface.ts b/src/models/ValidatorInterface.ts
index 5061a01a..26a4a79c 100644
--- a/src/models/ValidatorInterface.ts
+++ b/src/models/ValidatorInterface.ts
@@ -38,3 +38,8 @@ export interface ValidationPluginInterface extends ValidationPluginConstructor {
 export interface DriversMap {
   [index: string]: ValidationPluginInterface;
 }
+
+export enum ValidationHooks {
+  onSuccess = 'onSuccess',
+  onError = 'onError',
+}
\ No newline at end of file
diff --git a/src/props.ts b/src/props.ts
index 95aab9ad..c767d37a 100755
--- a/src/props.ts
+++ b/src/props.ts
@@ -1,4 +1,4 @@
-import { FieldPropsEnum } from "./models/FieldProps";
+import { FieldPropsEnum, FieldPropsOccurrence, SeparatedPropsMode } from "./models/FieldProps";
 
 export interface PropsGroupsInterface {
   editable: string[];
@@ -8,7 +8,7 @@ export interface PropsGroupsInterface {
   validation: string[];
   exceptions: string[];
   separated: string[];
-  types: {
+  occurrences: {
     [index: string]: "some" | "every";
   };
 }
@@ -62,22 +62,29 @@ export const props: PropsGroupsInterface = {
     FieldPropsEnum.disabled,
   ],
   separated: [
-    "values",
-    "initials",
-    "defaults",
-    "labels",
-    "placeholders",
-    "disabled",
-    "deleted",
-    "related",
-    "options",
-    "extra",
-    "bindings",
-    "types",
-    "hooks",
-    "handlers",
-    "autoFocus",
-    "refs"
+    SeparatedPropsMode.values,
+    SeparatedPropsMode.labels,
+    SeparatedPropsMode.placeholders,
+    SeparatedPropsMode.defaults,
+    SeparatedPropsMode.initials,
+    SeparatedPropsMode.disabled,
+    SeparatedPropsMode.deleted,
+    SeparatedPropsMode.types,
+    SeparatedPropsMode.related,
+    SeparatedPropsMode.rules,
+    SeparatedPropsMode.options,
+    SeparatedPropsMode.bindings,
+    SeparatedPropsMode.extra,
+    SeparatedPropsMode.hooks,
+    SeparatedPropsMode.handlers,
+    SeparatedPropsMode.validatedWith,
+    SeparatedPropsMode.validators,
+    SeparatedPropsMode.observers,
+    SeparatedPropsMode.interceptors,
+    SeparatedPropsMode.input,
+    SeparatedPropsMode.output,
+    SeparatedPropsMode.autoFocus,
+    SeparatedPropsMode.refs,
   ],
   functions: [
     FieldPropsEnum.observers,
@@ -94,19 +101,19 @@ export const props: PropsGroupsInterface = {
     FieldPropsEnum.isDirty,
     FieldPropsEnum.isPristine
   ],
-  types: {
-    isDirty: "some",
-    isPristine: "every",
-    isDefault: "every",
-    isValid: "every",
-    isEmpty: "every",
-    hasError: "some",
-    focused: "some",
-    blurred: "some",
-    touched: "some",
-    deleted: "every",
-    disabled: "every",
-    clearing: "every",
-    resetting: "every",
+  occurrences: {
+    isDirty: FieldPropsOccurrence.some,
+    isPristine: FieldPropsOccurrence.every,
+    isDefault: FieldPropsOccurrence.every,
+    isValid: FieldPropsOccurrence.every,
+    isEmpty: FieldPropsOccurrence.every,
+    hasError: FieldPropsOccurrence.some,
+    focused: FieldPropsOccurrence.some,
+    blurred: FieldPropsOccurrence.some,
+    touched: FieldPropsOccurrence.some,
+    deleted: FieldPropsOccurrence.every,
+    disabled: FieldPropsOccurrence.every,
+    clearing: FieldPropsOccurrence.every,
+    resetting: FieldPropsOccurrence.every,
   },
 };
diff --git a/src/utils.ts b/src/utils.ts
index b0439bb5..40983dc8 100755
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,7 +1,7 @@
 import _ from "lodash";
 import { ObservableMap, values as mobxValues, keys as mobxKeys } from "mobx";
 import FieldInterface from "./models/FieldInterface";
-import { FieldPropsEnum } from "./models/FieldProps";
+import { AllowedFieldPropsTypes, FieldPropsEnum, FieldPropsOccurrence } from "./models/FieldProps";
 import { props } from "./props";
 
 const getObservableMapValues = (observableMap: ObservableMap):
@@ -21,17 +21,12 @@ const checkObserveItem =
 const checkObserve = (collection: object[]) => (change: any) =>
   collection.map(checkObserveItem(change));
 
-const checkPropType = ({ type, data }: any) => {
+const checkPropOccurrence = ({ type, data }: any): boolean => {
   let $check: any;
   switch (type) {
-    case "some":
-      $check = ($data: object) => _.some($data, Boolean);
-      break;
-    case "every":
-      $check = ($data: object) => _.every($data, Boolean);
-      break;
-    default:
-      $check = null;
+    case FieldPropsOccurrence.some: $check = ($data: object) => _.some($data, Boolean); break;
+    case FieldPropsOccurrence.every: $check = ($data: object) => _.every($data, Boolean); break;
+    default: throw new Error('Occurrence not found for specified prop');
   }
   return $check(data);
 };
@@ -39,10 +34,17 @@ const checkPropType = ({ type, data }: any) => {
 const hasProps = ($type: any, $data: any) => {
   let $props;
   switch ($type) {
-    case "computed":
+    case AllowedFieldPropsTypes.computed:
       $props = props.computed;
       break;
-    case "field":
+    case AllowedFieldPropsTypes.observable:
+        $props = [
+          FieldPropsEnum.fields,
+          ...props.computed,
+          ...props.editable,
+        ];
+        break;
+    case AllowedFieldPropsTypes.editable:
       $props = [
         ...props.editable,
         ...props.validation,
@@ -50,9 +52,12 @@ const hasProps = ($type: any, $data: any) => {
         ...props.handlers,
       ];
       break;
-    case "all":
+    case AllowedFieldPropsTypes.all:
       $props = [
         FieldPropsEnum.id,
+        FieldPropsEnum.key,
+        FieldPropsEnum.name,
+        FieldPropsEnum.path,
         ...props.computed,
         ...props.editable,
         ...props.validation,
@@ -109,7 +114,7 @@ const $getKeys = (fields: any) =>
   _.union(..._.map(_.values(fields), (values) => _.keys(values)));
 
 const hasUnifiedProps = ({ fields }: any) =>
-  !isArrayOfStrings({ fields }) && hasProps("field", $getKeys(fields));
+  !isArrayOfStrings({ fields }) && hasProps(AllowedFieldPropsTypes.editable, $getKeys(fields));
 
 const hasSeparatedProps = (initial: any) =>
   hasSome(initial, props.separated) || hasSome(initial, props.validation);
@@ -123,8 +128,7 @@ const allowNested = (field: any, strictProps: boolean): boolean =>
     ...props.validation,
     ...props.functions,
     ...props.handlers,
-  ]) ||
-    strictProps);
+  ]) || strictProps);
 
 const parseIntKeys = (fields: any) =>
   _.map(getObservableMapKeys(fields), _.ary(_.toNumber, 1));
@@ -134,6 +138,7 @@ const hasIntKeys = (fields: any): boolean =>
 
 const maxKey = (fields: any): number => {
   const max = _.max(parseIntKeys(fields));
+  // @ts-ignore
   return _.isUndefined(max) ? 0 : max + 1;
 };
 
@@ -156,11 +161,8 @@ const $isBool = ($: any, val: any): boolean =>
 const $try = (...args: any) => {
   let found: any | null = null;
 
-  args.map(
-    (
-      val: any // eslint-disable-line
-    ) => found === null && !_.isUndefined(val) && (found = val)
-  );
+  args.map(( val: any ) =>
+    found === null && !_.isUndefined(val) && (found = val));
 
   return found;
 };
@@ -168,7 +170,7 @@ const $try = (...args: any) => {
 export {
   props,
   checkObserve,
-  checkPropType,
+  checkPropOccurrence,
   hasProps,
   allowedProps,
   throwError,
diff --git a/tests/fixes.values.ts b/tests/fixes.values.ts
index 4de46492..09003c2f 100755
--- a/tests/fixes.values.ts
+++ b/tests/fixes.values.ts
@@ -159,8 +159,8 @@ describe('Check Fixes $I values', () => {
 });
 
 describe('Check Fixes $M values', () => {
-  it('$M people[0].name value should be null', () =>
-    expect($.$M.$('people[0].name').value).to.be.null);
+  it('$M people[0].name value should be empty', () =>
+    expect($.$M.$('people[0].name').value).to.be.empty);
 
   it('$M items[0].name value should be equal to zero', () =>
     expect($.$M.$('items[0].name').value).to.be.equal(0));
diff --git a/tests/nested.validation.ts b/tests/nested.validation.ts
index 5572895e..76c1d271 100755
--- a/tests/nested.validation.ts
+++ b/tests/nested.validation.ts
@@ -23,6 +23,9 @@ describe('Check Nested $A validation', () => {
 });
 
 describe('Check Nested $U validation', () => {
+  it('$U user.email value should be false', () =>
+    expect($.$U.$('user.email').value).to.be.equal('notAnEmail'));
+
   it('$U user.emailConfirm isValid should be false', () =>
     expect($.$U.$('user.emailConfirm').isValid).to.be.false);