diff --git a/include/wx/filedlg.h b/include/wx/filedlg.h
index 65731b722b..fa53e25620 100644
--- a/include/wx/filedlg.h
+++ b/include/wx/filedlg.h
@@ -194,13 +194,13 @@ protected:
 
     wxWindow*     m_extraControl;
 
-    // returns true if control is created (if it already exists returns false)
+    // create and return the extra control using the given parent
+    wxWindow* CreateExtraControlWithParent(wxWindow* parent) const;
+    // returns true if control is created, also sets m_extraControl
     bool CreateExtraControl();
     // return true if SetExtraControlCreator() was called
     bool HasExtraControlCreator() const
         { return m_extraControlCreator != NULL; }
-    // get the size of the extra control by creating and deleting it
-    wxSize GetExtraControlSize();
     // Helper function for native file dialog usage where no wx events
     // are processed.
     void UpdateExtraControlUI();
diff --git a/src/common/fldlgcmn.cpp b/src/common/fldlgcmn.cpp
index d57b4b8110..09e0edfefc 100644
--- a/src/common/fldlgcmn.cpp
+++ b/src/common/fldlgcmn.cpp
@@ -368,35 +368,24 @@ bool wxFileDialogBase::SetExtraControlCreator(ExtraControlCreatorFunction creato
     return SupportsExtraControl();
 }
 
+wxWindow* wxFileDialogBase::CreateExtraControlWithParent(wxWindow* parent) const
+{
+    if ( m_extraControlCreator )
+        return (*m_extraControlCreator)(parent);
+
+    // It's not an error to call this function if there are no extra controls
+    // to create, just do nothing in this case.
+    return NULL;
+}
+
 bool wxFileDialogBase::CreateExtraControl()
 {
     // We're not supposed to be called more than once normally, but just do
     // nothing if we had already created the custom controls somehow.
-    if ( m_extraControl )
-        return true;
+    if ( !m_extraControl )
+        m_extraControl = CreateExtraControlWithParent(this);
 
-    if ( m_extraControlCreator )
-    {
-        m_extraControl = (*m_extraControlCreator)(this);
-
-        return true;
-    }
-
-    // It's not an error to call this function if there are no extra controls
-    // to create, just do nothing in this case.
-    return false;
-}
-
-wxSize wxFileDialogBase::GetExtraControlSize()
-{
-    if ( !m_extraControlCreator )
-        return wxDefaultSize;
-
-    // create the extra control in an empty dialog just to find its size: this
-    // is not terribly efficient but we do need to know the size before
-    // creating the native dialog and this seems to be the only way
-    wxDialog dlg(NULL, wxID_ANY, wxString());
-    return (*m_extraControlCreator)(&dlg)->GetSize();
+    return m_extraControl != NULL;
 }
 
 void wxFileDialogBase::UpdateExtraControlUI()
diff --git a/src/msw/filedlg.cpp b/src/msw/filedlg.cpp
index 94edf19a05..3f29a50584 100644
--- a/src/msw/filedlg.cpp
+++ b/src/msw/filedlg.cpp
@@ -1075,8 +1075,13 @@ int wxFileDialog::ShowCommFileDialog(WXHWND hWndParent)
         lpdt->x = 0;
         lpdt->y = 0;
 
+        // create the extra control in an empty dialog just to find its size: this
+        // is not terribly efficient but we do need to know the size before
+        // creating the native dialog and this seems to be the only way
+        wxDialog dlg(NULL, wxID_ANY, wxString());
+        const wxSize extraSize = CreateExtraControlWithParent(&dlg)->GetSize();
+
         // convert the size of the extra controls to the dialog units
-        const wxSize extraSize = GetExtraControlSize();
         const LONG baseUnits = ::GetDialogBaseUnits();
         lpdt->cx = ::MulDiv(extraSize.x, 4, LOWORD(baseUnits));
         lpdt->cy = ::MulDiv(extraSize.y, 8, HIWORD(baseUnits));