guessing at a fix

app.py

@@ -234,7 +234,7 @@ def reset_chat():
 def get_checkboxes():
     # rebuilding the list of checkboxes, so that these presets don't have to change
     # when adding a new control model
-    checkbox_column = app.children[2].children[0].children
+    checkbox_column = app.children[0].children[2].children[0].children
     model_names_and_indexes = {}
     checkbox_index = 0
     for i in range(len(checkbox_column)):