Index: mitk/Core/Code/DataManagement/mitkDisplayGeometry.cpp
===================================================================
--- mitk/Core/Code/DataManagement/mitkDisplayGeometry.cpp	(revision 24525)
+++ mitk/Core/Code/DataManagement/mitkDisplayGeometry.cpp	(working copy)
@@ -190,7 +190,6 @@
 
   if ( SetScaleFactor(m_ScaleFactorMMPerDisplayUnit/factor) )
   {
-    // only correct origin if zooming was ok
     return SetOriginInMM(m_OriginInMM-centerInDisplayUnits.GetVectorFromOrigin()*(1-factor)*m_ScaleFactorMMPerDisplayUnit);
   }
   else
@@ -199,6 +198,16 @@
   }
 }
 
+bool mitk::DisplayGeometry::ZoomWithFixFocus(ScalarType factor, const Point2D& focusDisplayUnits, const Point2D& focusUnitsInMM )
+{
+  assert(factor > 0);
+
+  SetScaleFactor(m_ScaleFactorMMPerDisplayUnit/factor);
+  SetOriginInMM(focusUnitsInMM.GetVectorFromOrigin()-focusDisplayUnits.GetVectorFromOrigin()*m_ScaleFactorMMPerDisplayUnit);
+  return true;
+}
+
+
 bool mitk::DisplayGeometry::MoveBy(const Vector2D& shiftInDisplayUnits)
 {
   SetOriginInMM(m_OriginInMM+shiftInDisplayUnits*m_ScaleFactorMMPerDisplayUnit);
@@ -452,14 +461,22 @@
   bool zoomYtooBig = displayHeightPx * m_ScaleFactorMMPerDisplayUnit < m_MinWorldViewPercentage * worldHeightMM;
 
   // constrain zooming in in x direction
-  if ( zoomXtooBig )
+  if ( zoomXtooBig && zoomYtooBig)
+  {
+    double fx = worldWidthMM * m_MinWorldViewPercentage / displayWidthPx;
+    double fy = worldHeightMM * m_MinWorldViewPercentage / displayHeightPx;
+    newScaleFactor = fx < fy ? fx : fy;
+    correctZooming = true;
+    }
+
+  else if ( zoomXtooBig )
   {
     newScaleFactor = worldWidthMM * m_MinWorldViewPercentage / displayWidthPx;
     correctZooming = true;
   }
 
   // constrain zooming in in y direction
-  if ( zoomYtooBig )
+  else if ( zoomYtooBig )
   {
     newScaleFactor = worldHeightMM * m_MinWorldViewPercentage / displayHeightPx;
     correctZooming = true;
@@ -497,7 +514,7 @@
   //
   // In both situations we center the not-maxed out direction
   //
-  if ( zoomXtooSmall && zoomYtooSmall )
+if ( zoomXtooSmall && zoomYtooSmall )
     {
       // determine and set the bigger scale factor
       float fx = worldWidthMM * m_MaxWorldViewPercentage / displayWidthPx;
@@ -507,8 +524,18 @@
       correctZooming = true;
     }
 
+
+  // actually execute correction
+  if (correctZooming)
+  {
+    SetScaleFactor(newScaleFactor);
+  }
+
+  displayWidthMM  = m_SizeInDisplayUnits[0] * m_ScaleFactorMMPerDisplayUnit;
+  displayHeightMM = m_SizeInDisplayUnits[1] * m_ScaleFactorMMPerDisplayUnit;
+
   // constrain panning
-  if (zoomXtooSmall)
+  if(worldWidthMM<displayWidthMM)
   {
     // zoomed out too much in x (but tolerated because y is still ok)
     // --> center x
@@ -524,8 +551,7 @@
       correctPanning = true;
     }
     // make sure right display border inside our world
-    else
-    if (displayXMM + displayWidthMM > worldWidthMM)
+    else  if (displayXMM + displayWidthMM > worldWidthMM)
     {
       newOrigin[0] = worldWidthMM - displayWidthMM;
       correctPanning = true;
@@ -533,7 +559,7 @@
   }
 
 
-  if (zoomYtooSmall)
+  if (worldHeightMM<displayHeightMM)
   {
     // zoomed out too much in y (but tolerated because x is still ok)
     // --> center y
@@ -542,28 +568,24 @@
   }
   else
   {
-    // make sure bottom display border inside our world
-    if (displayYMM < 0)
+    // make sure top display border inside our world
+    if (displayYMM + displayHeightMM >  worldHeightMM)
     {
-      newOrigin[1] = 0;
+      newOrigin[1] = worldHeightMM - displayHeightMM;
       correctPanning = true;
     }
-    // make sure top display border inside our world
+  // make sure bottom display border inside our world
     else
-    if (displayYMM + displayHeightMM >  worldHeightMM)
+    if (displayYMM < 0)
     {
-      newOrigin[1] = worldHeightMM - displayHeightMM;
+      newOrigin[1] = 0;
       correctPanning = true;
     }
-  }
 
-  // actually execute correction
-  if (correctZooming)
-  {
-    SetScaleFactor(newScaleFactor);
   }
 
-  if (correctPanning)
+
+ if (correctPanning)
   {
     SetOriginInMM( newOrigin );
   }
Index: mitk/Core/Code/DataManagement/mitkDisplayGeometry.h
===================================================================
--- mitk/Core/Code/DataManagement/mitkDisplayGeometry.h	(revision 24525)
+++ mitk/Core/Code/DataManagement/mitkDisplayGeometry.h	(working copy)
@@ -136,6 +136,10 @@
 
     // \return true if zoom request was within accepted limits
     virtual bool Zoom(ScalarType factor, const Point2D& centerInDisplayUnits);
+
+    // \return true if zoom request was within accepted limits
+    virtual bool ZoomWithFixFocus(ScalarType factor, const Point2D& focusDisplayUnits, const Point2D& focusUnitsInMM );
+
     // \return true if move request was within accepted limits
     virtual bool MoveBy(const Vector2D& shiftInDisplayUnits);
     
Index: mitk/Core/Code/Interactions/mitkDisplayCoordinateOperation.cpp
===================================================================
--- mitk/Core/Code/Interactions/mitkDisplayCoordinateOperation.cpp	(revision 24525)
+++ mitk/Core/Code/Interactions/mitkDisplayCoordinateOperation.cpp	(working copy)
@@ -33,6 +33,22 @@
 {
 }
 
+mitk::DisplayCoordinateOperation::DisplayCoordinateOperation(mitk::OperationType operationType,
+        mitk::BaseRenderer* renderer,
+        const mitk::Point2D& startDisplayCoordinate,
+        const mitk::Point2D& lastDisplayCoordinate,
+        const mitk::Point2D& currentDisplayCoordinate,
+        const mitk::Point2D& startCoordinateInMM
+)
+  : mitk::Operation(operationType),
+    m_Renderer(renderer),
+    m_StartDisplayCoordinate(startDisplayCoordinate),
+    m_LastDisplayCoordinate(lastDisplayCoordinate),
+    m_CurrentDisplayCoordinate(currentDisplayCoordinate),
+    m_StartCoordinateInMM(startCoordinateInMM)
+{
+}
+
 
 mitk::DisplayCoordinateOperation::~DisplayCoordinateOperation()
 {
Index: mitk/Core/Code/Interactions/mitkDisplayVectorInteractor.h
===================================================================
--- mitk/Core/Code/Interactions/mitkDisplayVectorInteractor.h	(revision 24525)
+++ mitk/Core/Code/Interactions/mitkDisplayVectorInteractor.h	(working copy)
@@ -66,6 +66,7 @@
     mitk::Point2D m_StartDisplayCoordinate;
     mitk::Point2D m_LastDisplayCoordinate;
     mitk::Point2D m_CurrentDisplayCoordinate;
+    mitk::Point2D m_StartCoordinateInMM;
 
     OperationActor* m_Destination;
   };
Index: mitk/Core/Code/Interactions/mitkDisplayCoordinateOperation.h
===================================================================
--- mitk/Core/Code/Interactions/mitkDisplayCoordinateOperation.h	(revision 24525)
+++ mitk/Core/Code/Interactions/mitkDisplayCoordinateOperation.h	(working copy)
@@ -46,6 +46,14 @@
       const mitk::Point2D& currentDisplayCoordinate
       );
 
+DisplayCoordinateOperation(mitk::OperationType operationType,
+      mitk::BaseRenderer* renderer,
+      const mitk::Point2D& startDisplayCoordinate,
+      const mitk::Point2D& lastDisplayCoordinate,
+      const mitk::Point2D& currentDisplayCoordinate,
+      const mitk::Point2D& startCoordinateInMM
+      );
+
     virtual ~DisplayCoordinateOperation();
 
     mitk::BaseRenderer* GetRenderer();
@@ -53,6 +61,7 @@
     mitkGetMacro(StartDisplayCoordinate, mitk::Point2D);
     mitkGetMacro(LastDisplayCoordinate, mitk::Point2D);
     mitkGetMacro(CurrentDisplayCoordinate, mitk::Point2D);
+    mitkGetMacro(StartCoordinateInMM, mitk::Point2D);
 
     mitk::Vector2D GetLastToCurrentDisplayVector();
     mitk::Vector2D GetStartToCurrentDisplayVector();
@@ -65,6 +74,7 @@
     const mitk::Point2D m_StartDisplayCoordinate;
     const mitk::Point2D m_LastDisplayCoordinate;
     const mitk::Point2D m_CurrentDisplayCoordinate;
+    const mitk::Point2D m_StartCoordinateInMM;
   };
 
 }
Index: mitk/Core/Code/Interactions/mitkDisplayVectorInteractor.cpp
===================================================================
--- mitk/Core/Code/Interactions/mitkDisplayVectorInteractor.cpp	(revision 24525)
+++ mitk/Core/Code/Interactions/mitkDisplayVectorInteractor.cpp	(working copy)
@@ -90,9 +90,14 @@
   case AcINITMOVE:
     {
       m_Sender=posEvent->GetSender();
+
+      mitk::Vector2D origin = m_Sender->GetDisplayGeometry()->GetOriginInMM();
+       double scaleFactorMMPerDisplayUnit = m_Sender->GetDisplayGeometry()->GetScaleFactorMMPerDisplayUnit();
+
       m_StartDisplayCoordinate=posEvent->GetDisplayPosition();
       m_LastDisplayCoordinate=posEvent->GetDisplayPosition();
       m_CurrentDisplayCoordinate=posEvent->GetDisplayPosition();
+      m_StartCoordinateInMM=mitk::Point2D( ( origin+m_StartDisplayCoordinate.GetVectorFromOrigin()*scaleFactorMMPerDisplayUnit ).GetDataPointer() );
       ok = true;
       break;
     }
@@ -123,7 +128,7 @@
     }
   case AcZOOM:
     {
-      DisplayCoordinateOperation* doOp = new DisplayCoordinateOperation(OpZOOM,  m_Sender, m_StartDisplayCoordinate, m_LastDisplayCoordinate, posEvent->GetDisplayPosition());
+      DisplayCoordinateOperation* doOp = new DisplayCoordinateOperation(OpZOOM,  m_Sender, m_StartDisplayCoordinate, m_LastDisplayCoordinate, posEvent->GetDisplayPosition(),m_StartCoordinateInMM);
       
       if (m_UndoEnabled)  //write to UndoMechanism
       {
Index: mitk/Core/Code/Interactions/mitkDisplayInteractor.cpp
===================================================================
--- mitk/Core/Code/Interactions/mitkDisplayInteractor.cpp	(revision 24525)
+++ mitk/Core/Code/Interactions/mitkDisplayInteractor.cpp	(working copy)
@@ -76,7 +76,7 @@
           // nothing to do, factor remains 1.0
         }
         
-        renderer->GetDisplayGeometry()->Zoom(factor, dcOperation->GetStartDisplayCoordinate());
+        renderer->GetDisplayGeometry()->ZoomWithFixFocus(factor, dcOperation->GetStartDisplayCoordinate(), dcOperation->GetStartCoordinateInMM());
         
         mitk::RenderingManager::GetInstance()->RequestUpdate(renderer->GetRenderWindow());
         ok = true;