diff --git a/rio/session/refresh_mixin.py b/rio/session/refresh_mixin.py
index 27a26180..e21fe336 100644
--- a/rio/session/refresh_mixin.py
+++ b/rio/session/refresh_mixin.py
@@ -856,7 +856,7 @@ class SessionRefreshMixin:
         old_component: rio.Component,
         new_component: rio.Component,
         reconciled_components_new_to_old: dict[rio.Component, rio.Component],
-    ) -> tuple[set[rio.Component], set[rio.Component]]:
+    ) -> None:
         """
         Given two components of the same type, reconcile them. Specifically:
 
@@ -919,26 +919,6 @@ class SessionRefreshMixin:
 
             overridden_values[prop_name] = new_value
 
-        # Keep track of added and removed child components
-        added_children = set[rio.Component]()
-        removed_children = set[rio.Component]()
-        if isinstance(
-            old_component, fundamental_component.FundamentalComponent
-        ):
-            child_containing_attributes = (
-                inspection.get_child_component_containing_attribute_names(
-                    type(old_component)
-                )
-            )
-
-            for attr_name in child_containing_attributes:
-                removed_children.update(
-                    extract_child_components(old_component, attr_name)
-                )
-                added_children.update(
-                    extract_child_components(new_component, attr_name)
-                )
-
         # If the component has changed, mark it as dirty
         def values_equal(old: object, new: object) -> bool:
             """
@@ -1007,8 +987,6 @@ class SessionRefreshMixin:
         # again
         old_component._on_populate_triggered_ = False
 
-        return added_children, removed_children
-
 
 def find_components_for_reconciliation(
     old_build: rio.Component,
diff --git a/rio/testing/base_client.py b/rio/testing/base_client.py
index 30bfd4f7..0d50b432 100644
--- a/rio/testing/base_client.py
+++ b/rio/testing/base_client.py
@@ -1,5 +1,6 @@
 import abc
 import asyncio
+import collections
 import typing as t
 
 import typing_extensions as te
@@ -190,7 +191,8 @@ class BaseClient(abc.ABC):
         component_type: type[C] = rio.Component,
         key: Key | None = None,
     ) -> t.Iterator[C]:
-        to_do = [self.root_component]
+        to_do = collections.deque()
+        to_do.append(self.root_component)
         to_do.extend(
             dialog._root_component
             for dialog in self.session._fundamental_root_component._owned_dialogs_.values()
@@ -198,7 +200,7 @@ class BaseClient(abc.ABC):
         seen = set[rio.Component]()
 
         while to_do:
-            component = to_do.pop()
+            component = to_do.popleft()
 
             if component in seen:
                 continue
diff --git a/tests/test_reconciliation.py b/tests/test_reconciliation.py
index 5b03b5eb..addb7624 100644
--- a/tests/test_reconciliation.py
+++ b/tests/test_reconciliation.py
@@ -350,16 +350,16 @@ async def test_margin_reconciliation():
 
         def build(self) -> rio.Component:
             if self.switch:
-                return rio.Column(*[rio.Text("hi") for _ in range(7)])
+                return rio.Column(*[rio.Text(f"{num}") for num in range(7)])
             else:
                 return rio.Column(
-                    rio.Text("hi", margin_left=1),
-                    rio.Text("hi", margin_right=1),
-                    rio.Text("hi", margin_top=1),
-                    rio.Text("hi", margin_bottom=1),
-                    rio.Text("hi", margin_x=1),
-                    rio.Text("hi", margin_y=1),
-                    rio.Text("hi", margin=1),
+                    rio.Text("0", margin_left=1),
+                    rio.Text("1", margin_right=1),
+                    rio.Text("2", margin_top=1),
+                    rio.Text("3", margin_bottom=1),
+                    rio.Text("4", margin_x=1),
+                    rio.Text("5", margin_y=1),
+                    rio.Text("6", margin=1),
                 )
 
     async with rio.testing.DummyClient(RootComponent) as test_client: