diff --git a/angular/headless/src/utils/widget.spec.ts b/angular/headless/src/utils/widget.spec.ts
index 4b3164ed77..5f27563359 100644
--- a/angular/headless/src/utils/widget.spec.ts
+++ b/angular/headless/src/utils/widget.spec.ts
@@ -47,6 +47,7 @@ describe('callWidgetFactoryWithConfig', () => {
 				{
 					onMyAction: typeFunction,
 					myValue: typeString,
+					onCounterChange: undefined,
 				},
 			);
 			const derivedValue$ = computed(createZoneCheckFn('computeDerivedValue', () => `derived from ${myValue$()}`));
diff --git a/core-bootstrap/src/components/alert/alert.ts b/core-bootstrap/src/components/alert/alert.ts
index a2b8ce1d46..b5800841fc 100644
--- a/core-bootstrap/src/components/alert/alert.ts
+++ b/core-bootstrap/src/components/alert/alert.ts
@@ -1,10 +1,10 @@
 import type {AlertDirectives, AlertState as CoreState, AlertProps as CoreProps, AlertApi} from '@agnos-ui/core/components/alert';
 import {createAlert as createCoreAlert, getAlertDefaultConfig as getCoreDefaultConfig} from '@agnos-ui/core/components/alert';
 import type {ConfigValidator, SlotContent, Widget, WidgetFactory, WidgetSlotContext} from '@agnos-ui/core/types';
-import {typeString} from '@agnos-ui/core/utils/writables';
+import {createTypeEnum} from '@agnos-ui/core/utils/writables';
 import {extendWidgetProps} from '@agnos-ui/core/services/extendWidget';
 import {fadeTransition} from '../../services/transitions';
-import type {BSContextualClass} from '../../types';
+import {BS_CONTEXTUAL_CLASSES, type BSContextualClass} from '../../types';
 import type {TransitionFn} from '@agnos-ui/core/services/transitions/baseTransitions';
 
 export * from '@agnos-ui/core/components/alert';
@@ -51,7 +51,9 @@ const coreOverride: Partial<CoreProps> = {
 	transition: fadeTransition,
 };
 const configValidator: ConfigValidator<AlertExtraProps> = {
-	type: typeString as any,
+	type: createTypeEnum(BS_CONTEXTUAL_CLASSES),
+	structure: undefined,
+	children: undefined,
 };
 
 /**
diff --git a/core-bootstrap/src/components/collapse/collapse.ts b/core-bootstrap/src/components/collapse/collapse.ts
index eaf68adfc9..5837010a54 100644
--- a/core-bootstrap/src/components/collapse/collapse.ts
+++ b/core-bootstrap/src/components/collapse/collapse.ts
@@ -2,7 +2,7 @@ import {createTransition} from '@agnos-ui/core/services/transitions/baseTransiti
 import type {ConfigValidator, Directive, PropsConfig, Widget} from '@agnos-ui/core/types';
 import {stateStores, writablesForProps} from '@agnos-ui/core/utils/stores';
 import {bindDirectiveNoArg} from '@agnos-ui/core/utils/directive';
-import {typeBoolean} from '@agnos-ui/core/utils/writables';
+import {typeBoolean, typeFunction, typeString} from '@agnos-ui/core/utils/writables';
 import {collapseHorizontalTransition, collapseVerticalTransition} from '../../services/transitions/collapse';
 import {asWritable, computed} from '@amadeus-it-group/tansu';
 
@@ -126,6 +126,13 @@ export function getCollapseDefaultConfig(): CollapseProps {
 
 const commonCollapseConfigValidator: ConfigValidator<CollapseProps> = {
 	horizontal: typeBoolean,
+	onVisibleChange: typeFunction,
+	onHidden: typeFunction,
+	onShown: typeFunction,
+	animatedOnInit: typeBoolean,
+	animated: typeBoolean,
+	className: typeString,
+	visible: typeBoolean,
 };
 
 /**
diff --git a/core-bootstrap/src/components/modal/modal.ts b/core-bootstrap/src/components/modal/modal.ts
index 4ed99ec295..bfedb99362 100644
--- a/core-bootstrap/src/components/modal/modal.ts
+++ b/core-bootstrap/src/components/modal/modal.ts
@@ -90,6 +90,12 @@ const coreOverride: Partial<CoreProps> = {
 
 const configValidator: ConfigValidator<ModalExtraProps<any>> = {
 	fullscreen: typeBoolean,
+	contentData: undefined,
+	children: undefined,
+	footer: undefined,
+	header: undefined,
+	structure: undefined,
+	title: undefined,
 };
 /**
  * Retrieve a shallow copy of the default modal config
diff --git a/core-bootstrap/src/components/pagination/pagination.ts b/core-bootstrap/src/components/pagination/pagination.ts
index 9753e0169f..4b3e5ae64d 100644
--- a/core-bootstrap/src/components/pagination/pagination.ts
+++ b/core-bootstrap/src/components/pagination/pagination.ts
@@ -129,4 +129,4 @@ export function getPaginationDefaultConfig(): PaginationProps {
  * @param config - an optional alert config
  * @returns a PaginationWidget
  */
-export const createPagination: WidgetFactory<PaginationWidget> = extendWidgetProps(createCorePagination, defaultConfigExtraProps, {});
+export const createPagination: WidgetFactory<PaginationWidget> = extendWidgetProps(createCorePagination, defaultConfigExtraProps);
diff --git a/core-bootstrap/src/components/progressbar/progressbar.ts b/core-bootstrap/src/components/progressbar/progressbar.ts
index 65afc0d5af..e5518e8d8f 100644
--- a/core-bootstrap/src/components/progressbar/progressbar.ts
+++ b/core-bootstrap/src/components/progressbar/progressbar.ts
@@ -1,9 +1,9 @@
 import type {ProgressbarDirectives, ProgressbarState as CoreState, ProgressbarProps as CoreProps} from '@agnos-ui/core/components/progressbar';
 import {createProgressbar as createCoreProgressbar, getProgressbarDefaultConfig as getCoreDefaultConfig} from '@agnos-ui/core/components/progressbar';
 import type {ConfigValidator, SlotContent, Widget, WidgetFactory, WidgetSlotContext} from '@agnos-ui/core/types';
-import {typeBoolean, typeString} from '@agnos-ui/core/utils/writables';
+import {createTypeEnum, typeBoolean, typeString} from '@agnos-ui/core/utils/writables';
 import {extendWidgetProps} from '@agnos-ui/core/services/extendWidget';
-import type {BSContextualClass} from '../../types';
+import {BS_CONTEXTUAL_CLASSES, type BSContextualClass} from '../../types';
 
 export * from '@agnos-ui/core/components/progressbar';
 
@@ -61,7 +61,9 @@ const configValidator: ConfigValidator<ProgressbarExtraProps> = {
 	height: typeString,
 	striped: typeBoolean,
 	animated: typeBoolean,
-	type: typeString as any,
+	type: createTypeEnum([undefined, ...BS_CONTEXTUAL_CLASSES]),
+	structure: undefined,
+	children: undefined,
 };
 
 /**
diff --git a/core-bootstrap/src/components/rating/rating.ts b/core-bootstrap/src/components/rating/rating.ts
index 79d80476eb..902002a05d 100644
--- a/core-bootstrap/src/components/rating/rating.ts
+++ b/core-bootstrap/src/components/rating/rating.ts
@@ -40,4 +40,4 @@ export function getRatingDefaultConfig(): RatingProps {
  * @returns a RatingWidget
  */
 
-export const createRating: WidgetFactory<RatingWidget> = extendWidgetProps(createCoreRating, defaultConfigExtraProps, {});
+export const createRating: WidgetFactory<RatingWidget> = extendWidgetProps(createCoreRating, defaultConfigExtraProps);
diff --git a/core-bootstrap/src/components/select/select.ts b/core-bootstrap/src/components/select/select.ts
index af7ad7f064..f37d41f02d 100644
--- a/core-bootstrap/src/components/select/select.ts
+++ b/core-bootstrap/src/components/select/select.ts
@@ -67,5 +67,4 @@ export function getSelectDefaultConfig(): SelectProps<any> {
 export const createSelect: <Item>(config?: PropsConfig<SelectProps<Item>>) => SelectWidget<Item> = extendWidgetProps(
 	createCoreSelect,
 	defaultConfigExtraProps,
-	{},
 ) as any;
diff --git a/core-bootstrap/src/components/slider/slider.ts b/core-bootstrap/src/components/slider/slider.ts
index d2a3691ac2..25ed8c535a 100644
--- a/core-bootstrap/src/components/slider/slider.ts
+++ b/core-bootstrap/src/components/slider/slider.ts
@@ -66,4 +66,4 @@ export function getSliderDefaultConfig(): SliderProps {
  * @returns a SliderWidget
  */
 
-export const createSlider: WidgetFactory<SliderWidget> = extendWidgetProps(createCoreSlider, defaultConfigExtraProps, {});
+export const createSlider: WidgetFactory<SliderWidget> = extendWidgetProps(createCoreSlider, defaultConfigExtraProps);
diff --git a/core-bootstrap/src/components/toast/toast.ts b/core-bootstrap/src/components/toast/toast.ts
index a88aee349f..0d8b55ecbe 100644
--- a/core-bootstrap/src/components/toast/toast.ts
+++ b/core-bootstrap/src/components/toast/toast.ts
@@ -60,4 +60,13 @@ export function getToastDefaultConfig(): ToastProps {
  * @param config - an optional alert config
  * @returns an ToastWidget
  */
-export const createToast: WidgetFactory<ToastWidget> = extendWidgetProps(createCoreToast, defaultConfigExtraProps, {}, coreOverride);
+export const createToast: WidgetFactory<ToastWidget> = extendWidgetProps(
+	createCoreToast,
+	defaultConfigExtraProps,
+	{
+		structure: undefined,
+		children: undefined,
+		header: undefined,
+	},
+	coreOverride,
+);
diff --git a/core-bootstrap/src/types.ts b/core-bootstrap/src/types.ts
index e49683e742..266ae3f450 100644
--- a/core-bootstrap/src/types.ts
+++ b/core-bootstrap/src/types.ts
@@ -1,2 +1,13 @@
 // Enumeration of all eight bootstrap contextual classes
 export type BSContextualClass = 'success' | 'info' | 'warning' | 'danger' | 'primary' | 'secondary' | 'light' | 'dark';
+
+export const BS_CONTEXTUAL_CLASSES: BSContextualClass[] = Object.values({
+	success: 'success',
+	info: 'info',
+	warning: 'warning',
+	danger: 'danger',
+	primary: 'primary',
+	secondary: 'secondary',
+	light: 'light',
+	dark: 'dark',
+} satisfies {[K in BSContextualClass]: K});
diff --git a/core/src/components/alert/common.ts b/core/src/components/alert/common.ts
index 1dfe7e8cd4..e0aa2de1ea 100644
--- a/core/src/components/alert/common.ts
+++ b/core/src/components/alert/common.ts
@@ -5,7 +5,7 @@ import type {ConfigValidator, Directive, PropsConfig, Widget} from '../../types'
 import {noop} from '../../utils/internal/func';
 import {stateStores, writablesForProps} from '../../utils/stores';
 import {bindDirectiveNoArg} from '../../utils/directive';
-import {typeBoolean} from '../../utils/writables';
+import {typeBoolean, typeFunction, typeString} from '../../utils/writables';
 
 export interface CommonAlertCommonPropsAndState extends WidgetsCommonPropsAndState {
 	/**
@@ -144,6 +144,15 @@ export function getCommonAlertDefaultConfig(): CommonAlertProps {
 
 const commonAlertConfigValidator: ConfigValidator<CommonAlertProps> = {
 	dismissible: typeBoolean,
+	onVisibleChange: typeFunction,
+	onHidden: typeFunction,
+	onShown: typeFunction,
+	transition: typeFunction,
+	animatedOnInit: typeBoolean,
+	animated: typeBoolean,
+	visible: typeBoolean,
+	ariaCloseButtonLabel: typeString,
+	className: typeString,
 };
 
 /**
diff --git a/core/src/components/pagination/pagination.ts b/core/src/components/pagination/pagination.ts
index f17ccf1537..17c27a52dd 100644
--- a/core/src/components/pagination/pagination.ts
+++ b/core/src/components/pagination/pagination.ts
@@ -1,9 +1,8 @@
 import {computed} from '@amadeus-it-group/tansu';
 import type {ReadableSignal} from '@amadeus-it-group/tansu';
-import {INVALID_VALUE} from '../../types';
 import {bindableProp, stateStores, writablesForProps} from '../../utils/stores';
 import {clamp, isNumber} from '../../utils/internal/checks';
-import {typeBoolean, typeFunction, typeNumber, typeString} from '../../utils/writables';
+import {createTypeEnum, typeBoolean, typeFunction, typeNumber, typeString} from '../../utils/writables';
 import type {ConfigValidator, PropsConfig, Widget, Directive} from '../../types';
 import {noop} from '../../utils/internal/func';
 import type {WidgetsCommonPropsAndState} from '../commonProps';
@@ -373,7 +372,7 @@ const configValidator: ConfigValidator<PaginationProps> = {
 	disabled: typeBoolean,
 	directionLinks: typeBoolean,
 	boundaryLinks: typeBoolean,
-	size: {normalizeValue: (value) => (value === 'lg' || value === 'sm' || value === null ? value : INVALID_VALUE)},
+	size: createTypeEnum(['lg', 'sm', null]),
 	onPageChange: typeFunction,
 	pagesFactory: typeFunction,
 	ariaLabel: typeString,
@@ -386,6 +385,7 @@ const configValidator: ConfigValidator<PaginationProps> = {
 	ariaLiveLabel: typeFunction,
 	className: typeString,
 	pageLink: typeFunction,
+	ariaEllipsisLabel: typeString,
 };
 
 /**
diff --git a/core/src/components/slider/slider.ts b/core/src/components/slider/slider.ts
index 8f9b305500..4994eca11e 100644
--- a/core/src/components/slider/slider.ts
+++ b/core/src/components/slider/slider.ts
@@ -6,7 +6,7 @@ import type {ConfigValidator, Directive, PropsConfig, Widget} from '../../types'
 import {noop} from '../../utils/internal/func';
 import {getDecimalPrecision} from '../../utils/internal/math';
 import {bindableProp, stateStores, writablesForProps} from '../../utils/stores';
-import {typeArray, typeBoolean, typeFunction, typeNumber, typeNumberInRangeFactory} from '../../utils/writables';
+import {typeArray, typeBoolean, typeFunction, typeNumber, typeNumberInRangeFactory, typeString} from '../../utils/writables';
 import {createResizeObserver} from '../../services/resizeObserver';
 
 export interface ProgressDisplayOptions {
@@ -317,6 +317,7 @@ const configValidator: ConfigValidator<SliderProps> = {
 	showValueLabels: typeBoolean,
 	showMinMaxLabels: typeBoolean,
 	rtl: typeBoolean,
+	className: typeString,
 };
 
 /**
diff --git a/core/src/types.ts b/core/src/types.ts
index 5a8b3f63c9..7f74d93200 100644
--- a/core/src/types.ts
+++ b/core/src/types.ts
@@ -101,7 +101,7 @@ export interface WritableWithDefaultOptions<T> {
 	equal?: StoreOptions<T>['equal'];
 }
 
-export type ConfigValidator<T extends object> = {[K in keyof T]?: WritableWithDefaultOptions<T[K]>};
+export type ConfigValidator<T extends object> = {[K in keyof T]: WritableWithDefaultOptions<T[K]> | undefined};
 
 export type AttributeValue = string | number | boolean | undefined;
 export type StyleKey = Exclude<
diff --git a/core/src/utils/internal/checks.spec.ts b/core/src/utils/internal/checks.spec.ts
index 032d708181..4b01cc26a1 100644
--- a/core/src/utils/internal/checks.spec.ts
+++ b/core/src/utils/internal/checks.spec.ts
@@ -1,5 +1,5 @@
 import {describe, expect, test, vi} from 'vitest';
-import {allowNull, clamp, isArray, isBoolean, isFunction, isHTMLElement, isNumber, isString} from './checks';
+import {allowNull, clamp, isArray, isBoolean, isFromEnum, isFunction, isHTMLElement, isNumber, isString} from './checks';
 
 describe('Checks', () => {
 	test(`'isNumber' should check if value is a number`, () => {
@@ -140,4 +140,11 @@ describe('Checks', () => {
 		expect(withAllowNull(0)).toBe(false);
 		expect(alwaysFalse).toHaveBeenCalledTimes(2);
 	});
+
+	test(`'isFromEnum' should check if the value is part of the array`, () => {
+		const emptyEnumCheck = isFromEnum([]);
+		expect(emptyEnumCheck('value')).toBe(false);
+		const uniqEnumCheck = isFromEnum(['value']);
+		expect(uniqEnumCheck('value')).toBe(true);
+	});
 });
diff --git a/core/src/utils/internal/checks.ts b/core/src/utils/internal/checks.ts
index b55e521446..cd8dce562c 100644
--- a/core/src/utils/internal/checks.ts
+++ b/core/src/utils/internal/checks.ts
@@ -68,3 +68,12 @@ export const allowNull =
 	<T>(isType: (value: any) => value is T) =>
 	(value: any): value is T | null =>
 		value === null || isType(value);
+
+/**
+ * Builds a new type guard to check if an element belongs to an enum list
+ * @param list - the list of all enum values
+ * @returns the type guard
+ */
+export function isFromEnum<T>(list: T[]) {
+	return (value: any): value is T => list.includes(value);
+}
diff --git a/core/src/utils/stores.spec.ts b/core/src/utils/stores.spec.ts
index 90e2e958e3..60ee05fbae 100644
--- a/core/src/utils/stores.spec.ts
+++ b/core/src/utils/stores.spec.ts
@@ -336,6 +336,7 @@ describe(`Stores service`, () => {
 							return value;
 						},
 					},
+					b: undefined,
 				},
 			);
 			const a: number[] = [];
diff --git a/core/src/utils/stores.ts b/core/src/utils/stores.ts
index 1428eb2a56..50214dd740 100644
--- a/core/src/utils/stores.ts
+++ b/core/src/utils/stores.ts
@@ -258,7 +258,7 @@ export const writablesWithDefault = <T extends object>(
 export const writablesForProps = <T extends object>(
 	defConfig: T,
 	propsConfig?: PropsConfig<T>,
-	options?: {[K in keyof T]?: WritableWithDefaultOptions<T[K]>},
+	options?: {[K in keyof T]: WritableWithDefaultOptions<T[K]> | undefined},
 ): [ToWritableSignal<T>, ReturnType<typeof createPatch<T>>] => {
 	const stores = writablesWithDefault(defConfig, propsConfig, options);
 	return [stores, createPatch(stores)];
diff --git a/core/src/utils/writables.ts b/core/src/utils/writables.ts
index f3fdbfd51c..9d4e29ab6d 100644
--- a/core/src/utils/writables.ts
+++ b/core/src/utils/writables.ts
@@ -1,4 +1,4 @@
-import {allowNull, clamp, isArray, isBoolean, isFunction, isHTMLElement, isNumber, isString} from './internal/checks';
+import {allowNull, clamp, isArray, isBoolean, isFromEnum, isFunction, isHTMLElement, isNumber, isString} from './internal/checks';
 import type {WritableWithDefaultOptions} from '../types';
 import {INVALID_VALUE} from '../types';
 
@@ -91,3 +91,15 @@ export const typeArray: WritableWithDefaultOptions<any[]> = {
 		}
 	},
 };
+
+/**
+ * Build an enum normalizer
+ * @template T - the enum type
+ * @param enumList - list of enum values to check
+ * @returns the enum normalizer
+ */
+export function createTypeEnum<T>(enumList: T[]): WritableWithDefaultOptions<T> {
+	return {
+		normalizeValue: testToNormalizeValue(isFromEnum(enumList)),
+	};
+}