From c5cb0100ff0960c6e8fa2b64cb6c5ef53adc4d82 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Fri, 24 Feb 2023 10:02:52 +0000
Subject: [PATCH 1/2] fix walk children

---
 src/textual/app.py      | 3 +++
 src/textual/reactive.py | 8 ++++----
 src/textual/walk.py     | 2 +-
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/textual/app.py b/src/textual/app.py
index 318dc3223..ed3adc280 100644
--- a/src/textual/app.py
+++ b/src/textual/app.py
@@ -2153,6 +2153,9 @@ class App(Generic[ReturnType], DOMNode):
             if widget.parent is not None:
                 widget.parent._nodes._remove(widget)
 
+        for node in pruned_remove:
+            node._detach()
+
         # Return the list of widgets that should end up being sent off in a
         # prune event.
         return pruned_remove
diff --git a/src/textual/reactive.py b/src/textual/reactive.py
index 0553d076c..f03624a0c 100644
--- a/src/textual/reactive.py
+++ b/src/textual/reactive.py
@@ -239,9 +239,10 @@ class Reactive(Generic[ReactiveType]):
                     )
                 )
 
-        watch_function = getattr(obj, f"watch_{name}", None)
-        if callable(watch_function):
-            invoke_watcher(watch_function, old_value, value)
+        if obj.is_attached:
+            watch_function = getattr(obj, f"watch_{name}", None)
+            if callable(watch_function):
+                invoke_watcher(watch_function, old_value, value)
 
         # Process "global" watchers
         watchers: list[tuple[Reactable, Callable]]
@@ -342,7 +343,6 @@ def _watch(
         callback: A callable to call when the attribute changes.
         init: True to call watcher initialization. Defaults to True.
     """
-
     if not hasattr(obj, "__watchers"):
         setattr(obj, "__watchers", {})
     watchers: dict[str, list[tuple[Reactable, Callable]]] = getattr(obj, "__watchers")
diff --git a/src/textual/walk.py b/src/textual/walk.py
index d43d40b06..0dc672471 100644
--- a/src/textual/walk.py
+++ b/src/textual/walk.py
@@ -53,7 +53,7 @@ def walk_depth_first(
     """
     from textual.dom import DOMNode
 
-    stack: list[Iterator[DOMNode]] = [iter(root._nodes)]
+    stack: list[Iterator[DOMNode]] = [iter(root.children)]
     pop = stack.pop
     push = stack.append
     check_type = filter_type or DOMNode

From 5a77e3493dd723a1000c94d233813c40581064f9 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Fri, 24 Feb 2023 10:13:58 +0000
Subject: [PATCH 2/2] add test

---
 CHANGELOG.md            |  2 ++
 src/textual/reactive.py |  7 +++----
 tests/test_screens.py   | 16 ++++++++++++++++
 3 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 042796b7b..52b700ef1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -30,6 +30,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Numbers in a descendant-combined selector no longer cause an error https://github.com/Textualize/textual/issues/1836
 - Fixed superfluous scrolling when focusing a docked widget https://github.com/Textualize/textual/issues/1816
+- Fixes walk_children which was returning more than one screen https://github.com/Textualize/textual/issues/1846
+- Fixed issue with watchers fired for detached nodes https://github.com/Textualize/textual/issues/1846
 
 ## [0.11.1] - 2023-02-17
 
diff --git a/src/textual/reactive.py b/src/textual/reactive.py
index f03624a0c..098ab031b 100644
--- a/src/textual/reactive.py
+++ b/src/textual/reactive.py
@@ -239,10 +239,9 @@ class Reactive(Generic[ReactiveType]):
                     )
                 )
 
-        if obj.is_attached:
-            watch_function = getattr(obj, f"watch_{name}", None)
-            if callable(watch_function):
-                invoke_watcher(watch_function, old_value, value)
+        watch_function = getattr(obj, f"watch_{name}", None)
+        if callable(watch_function):
+            invoke_watcher(watch_function, old_value, value)
 
         # Process "global" watchers
         watchers: list[tuple[Reactable, Callable]]
diff --git a/tests/test_screens.py b/tests/test_screens.py
index ca56df9c5..3edc5dce5 100644
--- a/tests/test_screens.py
+++ b/tests/test_screens.py
@@ -11,6 +11,22 @@ skip_py310 = pytest.mark.skipif(
 )
 
 
+async def test_screen_walk_children():
+    """Test query only reports active screen."""
+
+    class ScreensApp(App):
+        pass
+
+    app = ScreensApp()
+    async with app.run_test() as pilot:
+        screen1 = Screen()
+        screen2 = Screen()
+        pilot.app.push_screen(screen1)
+        assert list(pilot.app.query("*")) == [screen1]
+        pilot.app.push_screen(screen2)
+        assert list(pilot.app.query("*")) == [screen2]
+
+
 async def test_installed_screens():
     class ScreensApp(App):
         SCREENS = {