diff --git a/src/common/sizer.cpp b/src/common/sizer.cpp
index ea63c184c9..a8abbb3445 100644
--- a/src/common/sizer.cpp
+++ b/src/common/sizer.cpp
@@ -1947,12 +1947,16 @@ IMPLEMENT_CLASS(wxNotebookSizer, wxBookCtrlSizer)
 
 #if wxUSE_BOOKCTRL
 
+#if WXWIN_COMPATIBILITY_2_6
+
 wxBookCtrlSizer::wxBookCtrlSizer(wxBookCtrlBase *bookctrl)
                : m_bookctrl(bookctrl)
 {
     wxASSERT_MSG( bookctrl, wxT("wxBookCtrlSizer needs a control") );
 }
 
+#endif // WXWIN_COMPATIBILITY_2_6
+
 void wxBookCtrlSizer::RecalcSizes()
 {
     m_bookctrl->SetSize( m_position.x, m_position.y, m_size.x, m_size.y );