diff --git a/src/osgGLUT/Viewer.cpp b/src/osgGLUT/Viewer.cpp
index 66e286492..7b8685539 100644
--- a/src/osgGLUT/Viewer.cpp
+++ b/src/osgGLUT/Viewer.cpp
@@ -165,7 +165,7 @@ bool Viewer::open()
             selectCameraManipulator(0,index);
     }
 
-    GLUTEventAdapter::setWindowSize( _wx, _wy, _ww, _wh );
+    GLUTEventAdapter::setWindowSize( _wx, _wy, _wx+_ww, _wx+_wh );
     GLUTEventAdapter::setButtonMask(0);