Fix: saved views do not return to default display fields after setting and then removing (#9168)

src/documents/serialisers.py

@@ -1147,6 +1147,15 @@ class SavedViewSerializer(OwnedObjectSerializer):
         if "user" in validated_data:
             # backwards compatibility
             validated_data["owner"] = validated_data.pop("user")
+        if (
+            "display_fields" in validated_data
+            and isinstance(
+                validated_data["display_fields"],
+                list,
+            )
+            and len(validated_data["display_fields"]) == 0
+        ):
+            validated_data["display_fields"] = None
         super().update(instance, validated_data)
         if rules_data is not None:
             SavedViewFilterRule.objects.filter(saved_view=instance).delete()