diff --git a/include/wx/sizer.h b/include/wx/sizer.h
index ac8f5b6f34..89bdf66196 100644
--- a/include/wx/sizer.h
+++ b/include/wx/sizer.h
@@ -542,7 +542,11 @@ public:
                         int width,
                         int height,
                         const wxSizerFlags& flags);
-    virtual wxSizerItem* Insert( size_t index, wxSizerItem *item);
+
+    // NB: do _not_ override this function in the derived classes, this one is
+    //     virtual for compatibility reasons only to allow old code overriding
+    //     it to continue to work, override DoInsert() instead in the new code
+    virtual wxSizerItem* Insert(size_t index, wxSizerItem *item);
 
     wxSizerItem* InsertSpacer(size_t index, int size);
     wxSizerItem* InsertStretchSpacer(size_t index, int prop = 1);
@@ -713,6 +717,10 @@ protected:
     virtual bool DoSetItemMinSize( wxSizer *sizer, int width, int height );
     virtual bool DoSetItemMinSize( size_t index, int width, int height );
 
+    // insert a new item into m_children at given index and return the item
+    // itself
+    virtual wxSizerItem* DoInsert(size_t index, wxSizerItem *item);
+
 private:
     DECLARE_CLASS(wxSizer)
 };
@@ -733,13 +741,6 @@ public:
     wxGridSizer( int rows, int cols, int vgap, int hgap );
     wxGridSizer( int rows, int cols, const wxSize& gap );
 
-    virtual wxSizerItem *Insert(size_t index, wxSizerItem *item);
-
-#ifdef __WXOSX__
-    // TODO change to better condition
-    using wxSizer::Insert;
-#endif
-
     virtual void RecalcSizes();
     virtual wxSize CalcMin();
 
@@ -779,6 +780,8 @@ protected:
     int    m_vgap;
     int    m_hgap;
 
+    virtual wxSizerItem *DoInsert(size_t index, wxSizerItem *item);
+
     void SetItemBounds( wxSizerItem *item, int x, int y, int w, int h );
 
     // returns the number of columns/rows needed for the current total number
@@ -1271,6 +1274,12 @@ wxSizer::Insert( size_t index, int width, int height, const wxSizerFlags& flags
     return Insert( index, new wxSizerItem(width, height, flags) );
 }
 
+inline wxSizerItem*
+wxSizer::Insert(size_t index, wxSizerItem *item)
+{
+    return DoInsert(index, item);
+}
+
 inline wxSizerItem*
 wxSizer::InsertSpacer(size_t index, int size)
 {
diff --git a/src/common/sizer.cpp b/src/common/sizer.cpp
index 1325015a26..64ffc0877f 100644
--- a/src/common/sizer.cpp
+++ b/src/common/sizer.cpp
@@ -634,7 +634,7 @@ wxSizer::~wxSizer()
     WX_CLEAR_LIST(wxSizerItemList, m_children);
 }
 
-wxSizerItem* wxSizer::Insert( size_t index, wxSizerItem *item )
+wxSizerItem* wxSizer::DoInsert( size_t index, wxSizerItem *item )
 {
     m_children.Insert( index, item );
 
@@ -1349,7 +1349,7 @@ wxGridSizer::wxGridSizer( int rows, int cols, const wxSize& gap )
 {
 }
 
-wxSizerItem *wxGridSizer::Insert(size_t index, wxSizerItem *item)
+wxSizerItem *wxGridSizer::DoInsert(size_t index, wxSizerItem *item)
 {
     // if only the number of columns or the number of rows is specified for a
     // sizer, arbitrarily many items can be added to it but if both of them are
@@ -1379,7 +1379,7 @@ wxSizerItem *wxGridSizer::Insert(size_t index, wxSizerItem *item)
         }
     }
 
-    return wxSizer::Insert(index, item);
+    return wxSizer::DoInsert(index, item);
 }
 
 int wxGridSizer::CalcRowsCols(int& nrows, int& ncols) const