diff --git a/etg/dataobj.py b/etg/dataobj.py
index 5d48326d..66d581a4 100644
--- a/etg/dataobj.py
+++ b/etg/dataobj.py
@@ -132,6 +132,7 @@ def addBaseVirtuals(c):
         private:
         virtual size_t GetDataSize(const wxDataFormat& format) const;
         virtual bool   GetDataHere(const wxDataFormat& format, void* buf) const;
+        public:
         """))
 
 
diff --git a/unittests/test_dataobj.py b/unittests/test_dataobj.py
index d65ab338..a878e45e 100644
--- a/unittests/test_dataobj.py
+++ b/unittests/test_dataobj.py
@@ -254,6 +254,7 @@ class DataObjTests(wtc.WidgetTestCase):
         data1 = list(range(10))
         obj = wx.CustomDataObject('my custom format')
         obj.SetData(pickle.dumps(data1))
+        assert obj.GetDataSize() > 0
         data2 = pickle.loads(obj.GetData().tobytes())
         self.assertEqual(data1, data2)