diff --git a/python/graph_list_sort_filter_proxy_model.py b/python/graph_list_sort_filter_proxy_model.py
index ad3ddf8766bca07d2b25618c94314c30b1e9a373..b52dc0ab0252ce2c3de7f4d47889085f8c8a86ff 100644
--- a/python/graph_list_sort_filter_proxy_model.py
+++ b/python/graph_list_sort_filter_proxy_model.py
@@ -65,9 +65,9 @@ class GraphListSortFilterProxyModel(QSortFilterProxyModel):
 
         # hide_unmarked
         if self.hide_unmarked:
-            mark_index = super().sourceModel.index(
+            mark_index = super().sourceModel().index(
                                        row, MARK_COLUMN, source_parent)
-            if super().sourceModel.data(mark_index) != "M":
+            if super().sourceModel().data(mark_index) != "M":
                 return False
 
         # hide_unmatched_event_condition_traces