diff --git a/src/Mod/Show/TempoVis.py b/src/Mod/Show/TempoVis.py
index 999f8fdc5d..63cdfd9433 100644
--- a/src/Mod/Show/TempoVis.py
+++ b/src/Mod/Show/TempoVis.py
@@ -223,7 +223,7 @@ class TempoVis(FrozenClass):
             self.restore()
 
     def __getstate__(self):
-        return (self.data.items(), 
+        return (list(self.data.items()),
                 self.cam_string,
                 self.restore_on_delete)