diff --git a/PySimpleGUI.py b/PySimpleGUI.py
index 1971b3de..4ff5f9a0 100644
--- a/PySimpleGUI.py
+++ b/PySimpleGUI.py
@@ -3467,7 +3467,7 @@ def BuildResultsForSubform(form, initialize_only, top_level_form):
     button_pressed_text = top_level_form.LastButtonClicked
     for row_num, row in enumerate(form.Rows):
         for col_num, element in enumerate(row):
-            if element.Key is not None and  WRITE_ONLY_KEY in element.Key:
+            if element.Key is not None and  WRITE_ONLY_KEY in str(element.Key):
                 continue
             value = None
             if element.Type == ELEM_TYPE_COLUMN: