diff --git a/app/SubWindowHandle.cpp b/app/SubWindowHandle.cpp
index f6ecf82..05b22a5 100644
--- a/app/SubWindowHandle.cpp
+++ b/app/SubWindowHandle.cpp
@@ -58,12 +58,6 @@ Void SubWindowHandle::setMainWidget( QWidget *widget )
   m_cScrollArea->setWidget( widget );
 }
 
-Void SubWindowHandle::processZoomChange( Double scale, QPoint center )
-{
-  adjustScrollBarByScale( scale, center );
-  emit zoomChangedOnSubWindow();
-}
-
 QSize SubWindowHandle::getScrollSize()
 {
   return QSize(  m_cScrollArea->viewport()->size().width() - 5, m_cScrollArea->viewport()->size().height() - 5 );
diff --git a/app/SubWindowHandle.h b/app/SubWindowHandle.h
index 3d4e6a9..fa42088 100644
--- a/app/SubWindowHandle.h
+++ b/app/SubWindowHandle.h
@@ -47,8 +47,6 @@ private:
   UInt m_uiCategory;
   QString m_cWindowName;
 
-  Void adjustScrollBarByScale( Double scale, QPoint center );
-
 public:
   enum SubWindowCategories
   {
@@ -98,12 +96,12 @@ protected:
   QSize getScrollSize();
 
 Q_SIGNALS:
-  void zoomChangedOnSubWindow();
-  void scrollBarMoved( const QPoint );
+  void zoomFactorChanged_SWindow( const double, const QPoint );
+  void scrollBarMoved_SWindow( const QPoint );
   void updateStatusBar( const QString& );
 
 public Q_SLOTS:
-  void processZoomChange( double factor, QPoint center );
+  void adjustScrollBarByScale( double scale, QPoint center );
   void adjustScrollBarByOffset( QPoint Offset );
   void updateLastScrollValue();
 
diff --git a/app/VideoSubWindow.cpp b/app/VideoSubWindow.cpp
index 39e0106..1e378ad 100644
--- a/app/VideoSubWindow.cpp
+++ b/app/VideoSubWindow.cpp
@@ -83,9 +83,11 @@ VideoSubWindow::VideoSubWindow( QWidget * parent, Bool isModule ) :
 
   // Create a new interface to show images
   m_cViewArea = new ViewArea( this );
-  connect( m_cViewArea, SIGNAL( zoomFactorChanged( double , QPoint) ), this, SLOT( processZoomChange( double, QPoint ) ) );
-  connect( m_cViewArea, SIGNAL( moveScroll( QPoint ) ), this, SLOT( adjustScrollBarByOffset( QPoint ) ) );
-  connect( m_cViewArea, SIGNAL( moveScroll( QPoint ) ), this, SIGNAL( scrollBarMoved( QPoint ) ) );
+  connect( m_cViewArea, SIGNAL( zoomFactorChanged( double , QPoint) ), this, SLOT( adjustScrollBarByScale( double, QPoint ) ) );
+  connect( m_cViewArea, SIGNAL( zoomFactorChanged( double , QPoint) ), this, SIGNAL( zoomFactorChanged_SWindow( double, QPoint ) ) );
+
+  connect( m_cViewArea, SIGNAL( scrollBarMoved( QPoint ) ), this, SLOT( adjustScrollBarByOffset( QPoint ) ) );
+  connect( m_cViewArea, SIGNAL( scrollBarMoved( QPoint ) ), this, SIGNAL( scrollBarMoved_SWindow( QPoint ) ) );
 
   connect( m_cViewArea, SIGNAL( selectionChanged( QRect ) ), this, SLOT( updateSelectedArea( QRect ) ) );
   connect( m_cViewArea, SIGNAL( positionChanged( const QPoint & ) ), this, SLOT( updatePixelValueStatusBar( const QPoint & ) ) );
@@ -343,7 +345,10 @@ Void VideoSubWindow::normalSize()
   Double factor = 1.0;
   Double curFactor = getScaleFactor() ;
   if( factor != curFactor )
+  {
     m_cViewArea->scaleZoomFactor( factor/curFactor, QPoint() );
+    adjustScrollBarByScale( factor/curFactor, QPoint() );
+  }
 }
 
 Void VideoSubWindow::zoomToFit()
@@ -357,13 +362,20 @@ Void VideoSubWindow::zoomToFactor( Double factor , QPoint center )
   Double curFactor;
   curFactor = getScaleFactor() ;
   if( factor != curFactor )
+  {
     m_cViewArea->scaleZoomFactor( factor/curFactor, center );
+    adjustScrollBarByScale( factor/curFactor, center );
+  }
 }
 
 Void VideoSubWindow::scaleView( Double scale , QPoint center )
 {
   Q_ASSERT( m_cViewArea->image() );
-  m_cViewArea->scaleZoomFactor( scale, center );
+  if(scale!=1.0)
+  {
+    m_cViewArea->scaleZoomFactor( scale, center );
+    adjustScrollBarByScale( scale, center );
+  }
 }
 
 Void VideoSubWindow::scaleView( const QSize & size, QPoint center )
@@ -391,7 +403,10 @@ Void VideoSubWindow::scaleView( const QSize & size, QPoint center )
 
   Double curFactor = getScaleFactor() ;
   if( factor != curFactor )
+  {
     m_cViewArea->scaleZoomFactor( factor/curFactor, center );
+    adjustScrollBarByScale( factor/curFactor, center );
+  }
 }
 
 
diff --git a/app/ViewArea.cpp b/app/ViewArea.cpp
index 36436c0..b1262c0 100644
--- a/app/ViewArea.cpp
+++ b/app/ViewArea.cpp
@@ -109,17 +109,17 @@ Void ViewArea::setZoomFactor( Double f )
   update();
 }
 
-Void ViewArea::scaleZoomFactor( Double scale, QPoint center )
+int ViewArea::scaleZoomFactor( Double scale, QPoint center )
 {
   Double zoomFactor;
   Double maxZoom = 100.0;
   Double minZoom = 0.01;  //( 1.0 / m_pixmap.width() );
 
   if( ( m_zoomFactor == minZoom ) && ( scale < 1 ) )
-    return;
+    return 1;
 
   if( ( m_zoomFactor == maxZoom ) && ( scale > 1 ) )
-    return;
+    return 1;
 
   zoomFactor = m_zoomFactor * scale;
 
@@ -131,7 +131,7 @@ Void ViewArea::scaleZoomFactor( Double scale, QPoint center )
 
   setZoomFactor( zoomFactor );
 
-  emit zoomFactorChanged( scale, center );
+  return 0;
 }
 
 void ViewArea::setMode( ViewMode mode )
@@ -554,7 +554,8 @@ void ViewArea::wheelEvent( QWheelEvent *event )
     else
       scale=0.8;
 
-    scaleZoomFactor( scale , event->pos() );
+    if(scaleZoomFactor( scale , event->pos() ) == 0)
+      emit zoomFactorChanged( scale, event->pos() );
   }
 }
 
@@ -660,7 +661,7 @@ void ViewArea::mouseMoveEvent( QMouseEvent *event )
     if( tool() == NavigationTool )
     {
       QPoint offset = m_lastWindowPos - event->pos();
-      emit moveScroll( offset );
+      emit scrollBarMoved( offset );
     }
 
     updateRect = viewToWindow( m_selectedArea );
diff --git a/app/ViewArea.h b/app/ViewArea.h
index e66f5ec..1e18c55 100644
--- a/app/ViewArea.h
+++ b/app/ViewArea.h
@@ -115,7 +115,8 @@ public:
   void setInputStream( PlaYUVerStream *stream );
   PlaYUVerStream* getInputStream();
 
-  Void scaleZoomFactor(Double scale, QPoint center);
+  // Scale function. Return 0 when scale is performed. Return 1 otherwise
+  int scaleZoomFactor(Double scale, QPoint center);
 
   void setTool( eTool tool );
 
@@ -124,8 +125,8 @@ public:
 Q_SIGNALS:
   void selectionChanged( const QRect &rect );
   void positionChanged( const QPoint &pos );
-  void moveScroll( QPoint offset );
-  void zoomFactorChanged( double factor , QPoint center);
+  void scrollBarMoved( QPoint offset );
+  void zoomFactorChanged( const double factor , const QPoint center);
 
 public Q_SLOTS:
   void setNormalMode();
diff --git a/app/plaYUVerApp.cpp b/app/plaYUVerApp.cpp
index 8a3db8a..f08469d 100644
--- a/app/plaYUVerApp.cpp
+++ b/app/plaYUVerApp.cpp
@@ -195,8 +195,9 @@ Void plaYUVerApp::loadFile( QString fileName, PlaYUVerStreamInfo* pStreamInfo )
       connect( videoSubWindow->getViewArea(), SIGNAL( selectionChanged( QRect ) ), m_appModuleVideo, SLOT( updateSelectionArea( QRect ) ) );
 
       connect( subWindow, SIGNAL( updateStatusBar( const QString& ) ), this, SLOT( updateStatusBar( const QString& ) ) );
-      connect( subWindow, SIGNAL( zoomChangedOnSubWindow() ), this, SLOT( updateZoomFactorSBox() ) );
-      connect( subWindow, SIGNAL( scrollBarMoved( const QPoint ) ), this, SLOT( moveAllScrollBars( const QPoint ) ) );
+      connect( subWindow, SIGNAL( zoomFactorChanged_SWindow( const double, const QPoint ) ), this, SLOT( updateZoomFactorSBox() ) );
+      connect( subWindow, SIGNAL( zoomFactorChanged_SWindow( const double, const QPoint ) ), this, SLOT( zoomToFactorAll( double, QPoint ) ) );
+      connect( subWindow, SIGNAL( scrollBarMoved_SWindow( const QPoint ) ), this, SLOT( moveAllScrollBars( const QPoint ) ) );
 
       videoSubWindow->zoomToFit();
       videoSubWindow->getViewArea()->setTool( m_appTool );
@@ -417,8 +418,13 @@ Void plaYUVerApp::zoomToFitAll()
     updateZoomFactorSBox();
 }
 
-Void plaYUVerApp::zoomToFactorAll( double factor )
+Void plaYUVerApp::zoomToFactorAll( const double scale, const QPoint center )
 {
+  qDebug() << scale << center;
+  double factor;
+  if( m_pcCurrentSubWindow )
+    factor = m_pcCurrentSubWindow->getScaleFactor();
+
   SubWindowHandle *subWindow;
   for( Int i = 0; i < mdiArea->subWindowList().size(); i++ )
   {
@@ -426,7 +432,9 @@ Void plaYUVerApp::zoomToFactorAll( double factor )
     if( m_pcCurrentSubWindow == subWindow )
       continue;
     else
-      subWindow->zoomToFactor(factor);
+    {
+      subWindow->zoomToFactor( factor , center );
+    }
   }
 }
 
@@ -446,21 +454,16 @@ Void plaYUVerApp::zoomFromSBox( double zoom )
   {
     activeSubWindow()->zoomToFactor( factor );
   }
-
-  zoomToFactorAll( factor );
 }
 
-Void plaYUVerApp::updateZoomFactorSBox()
+Void plaYUVerApp::updateZoomFactorSBox( )
 {
+  Double factor;
   if( m_pcCurrentSubWindow )
   {
-    Double factor = m_pcCurrentSubWindow->getScaleFactor();
+    factor = m_pcCurrentSubWindow->getScaleFactor();
     m_pcZoomFactorSBox->setValue( factor * 100 );
   }
-  else
-  {
-    m_pcZoomFactorSBox->setValue( 0.0 );
-  }
 }
 
 Void plaYUVerApp::moveAllScrollBars( const QPoint offset )
diff --git a/app/plaYUVerApp.h b/app/plaYUVerApp.h
index 255ddfc..ffa4a8a 100644
--- a/app/plaYUVerApp.h
+++ b/app/plaYUVerApp.h
@@ -89,7 +89,7 @@ private Q_SLOTS:
   void normalSize();
   void zoomToFit();
   void zoomToFitAll();
-  void zoomToFactorAll( double factor );
+  void zoomToFactorAll( const double factor, const QPoint center = QPoint() );
 
   void setTool( int idxTool );