diff --git a/etg/toplevel.py b/etg/toplevel.py
index 6b08c5ac..658f371e 100644
--- a/etg/toplevel.py
+++ b/etg/toplevel.py
@@ -78,6 +78,7 @@ def run():
     c.addProperty('MacMetalAppearance MacGetMetalAppearance MacSetMetalAppearance')
     
     tools.fixTopLevelWindowClass(c)
+    c.find('ShouldPreventAppExit').isVirtual = True
     
     #-----------------------------------------------------------------
     tools.doCommonTweaks(module)