expand docstring

Author: ElLorans

flask_admin/model/form.py

@@ -53,9 +53,15 @@ def create_editable_list_form(
         widget = HTMXEditableWidget()
 
     class ListForm(BaseListForm, form_base_class):  # type: ignore[misc, valid-type]
-        # Stores the original flask-admin widgets (DatePickerWidget, etc.)
-        # before they get replaced with the display widget (HTMXEditableWidget).
-        # Used by ajax_edit/ajax_update to restore proper input widgets.
+        """
+        Stores the original flask-admin widgets (DatePickerWidget, etc.)
+        before they get replaced with the display widget (HTMXEditableWidget).
+        Used by ajax_edit/ajax_update to restore proper input widgets.
+        _original_widgets dict must be per-invocation, so do not move the class def
+        outside of the function unless making the dict instance-level instead of
+        class-level.
+        """
+
         _original_widgets: dict[str, t.Any] = {}
 
     # iterate FormMeta to get unbound fields, replace widget, copy to ListForm