diff --git a/etg/toplevel.py b/etg/toplevel.py
index 79f28b3e..e66b8ec1 100644
--- a/etg/toplevel.py
+++ b/etg/toplevel.py
@@ -67,6 +67,8 @@ def run():
         #endif
         """)
 
+    c.find('GeometrySerializer').abstract = True
+
     c.addProperty('DefaultItem GetDefaultItem SetDefaultItem')
     c.addProperty('Icon GetIcon SetIcon')
     c.addProperty('Title GetTitle SetTitle')