diff --git a/Core/Code/Interactions/mitkMouseWheelEvent.cpp b/Core/Code/Interactions/mitkMouseWheelEvent.cpp
index b6c05a4355..f35a5c84d0 100644
--- a/Core/Code/Interactions/mitkMouseWheelEvent.cpp
+++ b/Core/Code/Interactions/mitkMouseWheelEvent.cpp
@@ -1,76 +1,76 @@
 /*===================================================================
 
  The Medical Imaging Interaction Toolkit (MITK)
 
  Copyright (c) German Cancer Research Center,
  Division of Medical and Biological Informatics.
  All rights reserved.
 
  This software is distributed WITHOUT ANY WARRANTY; without
  even the implied warranty of MERCHANTABILITY or FITNESS FOR
  A PARTICULAR PURPOSE.
 
  See LICENSE.txt or http://www.mitk.org for details.
 
  ===================================================================*/
 
 #include "mitkMouseWheelEvent.h"
 
 mitk::MouseWheelEvent::MouseWheelEvent(BaseRenderer* baseRenderer,
     const Point2D& mousePosition,
     MouseButtons buttonStates,
     ModifierKeys modifiers,
     int wheelDelta)
 : InteractionPositionEvent(baseRenderer, mousePosition)
 , m_WheelDelta(wheelDelta)
 , m_ButtonStates(buttonStates)
 , m_Modifiers(modifiers)
 {
 }
 
 int mitk::MouseWheelEvent::GetWheelDelta() const
 {
   return m_WheelDelta;
 }
 
 void mitk::MouseWheelEvent::SetWheelDelta(int delta)
 {
   m_WheelDelta = delta;
 }
 
 mitk::InteractionEvent::ModifierKeys mitk::MouseWheelEvent::GetModifiers() const
 {
   return m_Modifiers;
 }
 
 mitk::InteractionEvent::MouseButtons mitk::MouseWheelEvent::GetButtonStates() const
 {
   return m_ButtonStates;
 }
 
 void mitk::MouseWheelEvent::SetModifiers(ModifierKeys modifiers)
 {
   m_Modifiers = modifiers;
 }
 
 void mitk::MouseWheelEvent::SetButtonStates(MouseButtons buttons)
 {
   m_ButtonStates = buttons;
 }
 
 mitk::MouseWheelEvent::~MouseWheelEvent()
 {
 }
 
 bool mitk::MouseWheelEvent::IsEqual(const mitk::InteractionEvent& interactionEvent) const
 {
   const mitk::MouseWheelEvent& mwe = static_cast<const MouseWheelEvent&>(interactionEvent);
-  return ((this->GetWheelDelta() * mwe.GetWheelDelta() > 0) // Consider WheelEvents to be equal if the scrolling is done in the same direction.
+  return ((this->GetWheelDelta() * mwe.GetWheelDelta() >= 0) // Consider WheelEvents to be equal if the scrolling is done in the same direction.
           && this->GetModifiers() == mwe.GetModifiers() && this->GetButtonStates() == mwe.GetButtonStates() &&
           Superclass::IsEqual(interactionEvent));
 }
 
 bool mitk::MouseWheelEvent::IsSuperClassOf(const InteractionEvent::Pointer& baseClass) const
 {
   return (dynamic_cast<MouseWheelEvent*>(baseClass.GetPointer()) != NULL) ;
 }