diff --git a/include/wx/sizer.h b/include/wx/sizer.h
index 73d99c2779..e815822be2 100644
--- a/include/wx/sizer.h
+++ b/include/wx/sizer.h
@@ -678,14 +678,14 @@ private:
 
 #if wxUSE_STATBOX
 
-#include "wx/statbox.h"
+class WXDLLEXPORT wxStaticBox;
 
 class WXDLLEXPORT wxStaticBoxSizer: public wxBoxSizer
 {
 public:
     wxStaticBoxSizer(wxStaticBox *box, int orient);
     wxStaticBoxSizer(int orient, wxWindow *win, const wxString& label = wxEmptyString);
-    virtual ~wxStaticBoxSizer() { delete m_staticBox; }
+    virtual ~wxStaticBoxSizer();
 
     void RecalcSizes();
     wxSize CalcMin();
diff --git a/src/common/sizer.cpp b/src/common/sizer.cpp
index 4542871dd8..92377a0d0a 100644
--- a/src/common/sizer.cpp
+++ b/src/common/sizer.cpp
@@ -1715,6 +1715,11 @@ wxStaticBoxSizer::wxStaticBoxSizer(int orient, wxWindow *win, const wxString& s)
     m_staticBox->SetContainingSizer(this);
 }
 
+wxStaticBoxSizer::~wxStaticBoxSizer()
+{
+    delete m_staticBox;
+}
+
 static void GetStaticBoxBorders( wxStaticBox *box,
                                  int *borderTop,
                                  int *borderOther)