diff --git a/sources/ewol/widget/ContainerN.cpp b/sources/ewol/widget/ContainerN.cpp
index e824f6e4..d5b19a0c 100644
--- a/sources/ewol/widget/ContainerN.cpp
+++ b/sources/ewol/widget/ContainerN.cpp
@@ -68,14 +68,14 @@ int32_t widget::ContainerN::SubWidgetAdd(ewol::Widget* _newWidget)
 	MarkToRedraw();
 	ewol::RequestUpdateSize();
 	// added at the last eelement :
-	return m_subWidget.Size()-1;
+	return _newWidget->GetId();
 }
 
-void widget::ContainerN::SubWidgetAddStart(ewol::Widget* _newWidget)
+int32_t widget::ContainerN::SubWidgetAddStart(ewol::Widget* _newWidget)
 {
 	if (NULL == _newWidget) {
 		EWOL_ERROR("[" << GetId() << "] {" << GetObjectType() << "} Try to add start An empty Widget ... ");
-		return;
+		return -1;
 	}
 	if (_newWidget!=NULL) {
 		_newWidget->SetUpperWidget(this);
@@ -83,6 +83,7 @@ void widget::ContainerN::SubWidgetAddStart(ewol::Widget* _newWidget)
 	m_subWidget.PushFront(_newWidget);
 	MarkToRedraw();
 	ewol::RequestUpdateSize();
+	return _newWidget->GetId();
 }
 
 void widget::ContainerN::SubWidgetRemove(ewol::Widget* _newWidget)
diff --git a/sources/ewol/widget/ContainerN.h b/sources/ewol/widget/ContainerN.h
index f67053f7..892f4fa4 100644
--- a/sources/ewol/widget/ContainerN.h
+++ b/sources/ewol/widget/ContainerN.h
@@ -54,6 +54,7 @@ namespace widget
 			/**
 			 * @brief Add at end position a Widget (note : This system use an inverted phylisophie (button to top, and left to right)
 			 * @param[in] _newWidget the element pointer
+			 * @return the ID of the set element
 			 */
 			virtual int32_t SubWidgetAdd(ewol::Widget* _newWidget);
 			inline  int32_t SubWidgetAddBack(ewol::Widget* _newWidget) { return SubWidgetAdd(_newWidget); };
@@ -61,9 +62,10 @@ namespace widget
 			/**
 			 * @brief Add at start position a Widget (note : This system use an inverted phylisophie (button to top, and left to right)
 			 * @param[in] _newWidget the element pointer
+			 * @return the ID of the set element
 			 */
-			virtual void SubWidgetAddStart(ewol::Widget* _newWidget);
-			inline  void SubWidgetAddFront(ewol::Widget* _newWidget) { SubWidgetAddStart(_newWidget); };
+			virtual int32_t SubWidgetAddStart(ewol::Widget* _newWidget);
+			inline  int32_t SubWidgetAddFront(ewol::Widget* _newWidget) { return SubWidgetAddStart(_newWidget); };
 			/**
 			 * @brief Remove definitly a widget from the system and this layer.
 			 * @param[in] _newWidget the element pointer.
diff --git a/sources/ewol/widget/Sizer.cpp b/sources/ewol/widget/Sizer.cpp
index 4300a81a..56644ed1 100644
--- a/sources/ewol/widget/Sizer.cpp
+++ b/sources/ewol/widget/Sizer.cpp
@@ -32,13 +32,18 @@ void widget::Sizer::UnInit(void)
 
 widget::Sizer::Sizer(widget::Sizer::displayMode_te _mode):
 	m_mode(_mode),
-	m_borderSize()
+	m_borderSize(),
+	m_animation(animationNone),
+	m_animationTime(0)
 {
 	
 }
 
 widget::Sizer::~Sizer(void)
 {
+	// disable annimation to remore "remove" error
+	m_animation = animationNone;
+	m_animationTime = 0;
 	//EWOL_DEBUG("[" << GetId() << "]={" << GetObjectType() << "}  Sizer : destroy (mode=" << (m_mode==widget::Sizer::modeVert?"Vert":"Hori") << ")");
 }
 
@@ -199,3 +204,44 @@ bool widget::Sizer::LoadXML(TiXmlNode* _node)
 }
 
 
+
+int32_t widget::Sizer::SubWidgetAdd(ewol::Widget* _newWidget)
+{
+	if (m_animation == animationNone) {
+		return widget::ContainerN::SubWidgetAdd(_newWidget);
+	}
+	// TODO : ...
+	return widget::ContainerN::SubWidgetAdd(_newWidget);
+}
+
+int32_t widget::Sizer::SubWidgetAddStart(ewol::Widget* _newWidget)
+{
+	if (m_animation == animationNone) {
+		return widget::ContainerN::SubWidgetAddStart(_newWidget);
+	}
+	// TODO : ...
+	return widget::ContainerN::SubWidgetAddStart(_newWidget);
+}
+
+void widget::Sizer::SubWidgetRemove(ewol::Widget* _newWidget)
+{
+	if (m_animation == animationNone) {
+		widget::ContainerN::SubWidgetRemove(_newWidget);
+		return;
+	}
+	// TODO : ...
+	widget::ContainerN::SubWidgetRemove(_newWidget);
+}
+
+void widget::Sizer::SubWidgetUnLink(ewol::Widget* _newWidget)
+{
+	if (m_animation == animationNone) {
+		widget::ContainerN::SubWidgetUnLink(_newWidget);
+		return;
+	}
+	// TODO : ...
+	widget::ContainerN::SubWidgetUnLink(_newWidget);
+}
+
+
+
diff --git a/sources/ewol/widget/Sizer.h b/sources/ewol/widget/Sizer.h
index 78dad0c0..776255c9 100644
--- a/sources/ewol/widget/Sizer.h
+++ b/sources/ewol/widget/Sizer.h
@@ -65,11 +65,51 @@ namespace widget {
 			 * @return the border size (0 if not used)
 			 */
 			const ewol::Dimension& GetBorderSize(void) { return m_borderSize; };
+		public:
+			typedef enum {
+				animationNone, //!< No annimation
+				animationTop, //!< element came from the top
+				animationbuttom, //!< element came from the buttom
+				animationLeft, //!< element came from the Left
+				animationRight //!< element came from the right
+				//animationZoom //!< element came from zooming
+			} animation_te;
+		private:
+			animation_te m_animation; //!< Methode add and remove element (animation)
+		public:
+			/**
+			 * @brief Set an animation mode for the new element set in the Widget container.
+			 * @param[in] _animation The new animation mode.
+			 */
+			void SetAnimationMode(animation_te _animation) { m_animation = _animation; };
+			/**
+			 * @brief Get the current animation mode.
+			 * @return The animation mode.
+			 */
+			animation_te GetAnimationMode(void) { return m_animation;};
+		private:
+			float m_animationTime; //!< Time in second to generate animation
+		public:
+			/**
+			 * @brief Set the time to produce animation.
+			 * @param[in] _time The new animation time.
+			 */
+			void SetAnimationTime(float _time) { m_animationTime = _time; };
+			/**
+			 * @brief Get the current animation time.
+			 * @return The time to produce the animation.
+			 */
+			float GetAnimationTime(void) { return m_animationTime;};
 		public: // Derived function
 			virtual const char * const GetObjectType(void) { return "ewol::widget::sizer"; };
 			virtual void CalculateSize(const vec2& _availlable);
 			virtual void CalculateMinMaxSize(void);
 			virtual bool LoadXML(TiXmlNode* _node);
+			// overwrite the set fuction to start annimations ...
+			virtual int32_t SubWidgetAdd(ewol::Widget* _newWidget);
+			virtual int32_t SubWidgetAddStart(ewol::Widget* _newWidget);
+			virtual void SubWidgetRemove(ewol::Widget* _newWidget);
+			virtual void SubWidgetUnLink(ewol::Widget* _newWidget);
 	};
 	
 };
diff --git a/sources/ewol/widget/WSlider.cpp b/sources/ewol/widget/WSlider.cpp
index 3c882dcb..8b63996e 100644
--- a/sources/ewol/widget/WSlider.cpp
+++ b/sources/ewol/widget/WSlider.cpp
@@ -123,11 +123,23 @@ void widget::WSlider::CalculateSize(const vec2& _availlable)
 
 void widget::WSlider::SubWidgetSelectSet(int32_t _id)
 {
-	if (_id<0 || _id >= m_subWidget.Size()) {
-		EWOL_ERROR("Can not change to a widget not present");
+	int32_t elementID = -1;
+	// search element in the list : 
+	for( int32_t iii=0 ; iii<m_subWidget.Size() ; iii++) {
+		if (m_subWidget[iii] != NULL) {
+			if (m_subWidget[iii]->GetId()==_id) {
+				elementID = iii;
+				break;
+			}
+		}
 	}
-	if (_id != m_windowsDestination) {
-		m_windowsRequested = _id;
+
+	if (elementID<0) {
+		EWOL_ERROR("Can not change to a widget not present : uid="<<_id);
+		return;
+	}
+	if (elementID != m_windowsDestination) {
+		m_windowsRequested = elementID;
 		GenerateEventId(eventStartSlide);
 		PeriodicCallEnable();
 		MarkToRedraw();