diff --git a/examples/osgtessellationshaders/osgtessellationshaders.cpp b/examples/osgtessellationshaders/osgtessellationshaders.cpp
index ab1e6d1d3..04235700c 100644
--- a/examples/osgtessellationshaders/osgtessellationshaders.cpp
+++ b/examples/osgtessellationshaders/osgtessellationshaders.cpp
@@ -171,6 +171,10 @@ osg::ref_ptr<osg::Geode> CreateIcosahedron(osg::Program *program)
     geometry->setVertexArray(vertices);
     geometry->addPrimitiveSet(new osg::DrawElementsUInt(osg::PrimitiveSet::PATCHES,IndexCount,Faces));
 
+    // Expand the bounding box, otherwise the geometry is clipped in front when tessellating.
+    osg::BoundingBox bbox(osg::Vec3(-1.0f, -1.9f, -1.0f), osg::Vec3(1.0f, 1.0f, 1.0f));
+    geometry->setInitialBound(bbox);
+
     geode->addDrawable(geometry);
     return geode;
 }
diff --git a/include/osg/GLDefines b/include/osg/GLDefines
index 393c666cc..094211129 100644
--- a/include/osg/GLDefines
+++ b/include/osg/GLDefines
@@ -177,7 +177,7 @@ typedef char GLchar;
 #define GL_FRAMEBUFFER_SRGB               0x8DB9
 #endif
 
-#ifndef EXT_geometry_shader4
+#ifndef GL_EXT_geometry_shader4
 #define GL_GEOMETRY_VERTICES_OUT_EXT            0x8DDA
 #define GL_GEOMETRY_INPUT_TYPE_EXT              0x8DDB
 #define GL_GEOMETRY_OUTPUT_TYPE_EXT             0x8DDC