removed cruft

src/textual/app.py

@@ -733,10 +733,17 @@ class App(Generic[ReturnType], DOMNode):
             str | None: The name of the screen that was uninstalled, or None if no screen was uninstalled.
         """
         if isinstance(screen, str):
-            uninstalled_screen = self._installed_screens.pop(screen)
-            self.log(f"{uninstalled_screen} UNINSTALLED name={screen!r}")
+            if screen not in self._installed_screens:
+                return None
+            uninstall_screen = self._installed_screens[screen]
+            if uninstall_screen in self._screen_stack:
+                raise ScreenStackError("Can't uninstall screen in screen stack")
+            del self._installed_screens[screen]
+            self.log(f"{uninstall_screen} UNINSTALLED name={screen!r}")
             return screen
         else:
+            if screen in self._screen_stack:
+                raise ScreenStackError("Can't uninstall screen in screen stack")
             for name, installed_screen in self._installed_screens.items():
                 if installed_screen is screen:
                     self._installed_screens.pop(name)

src/textual/dom.py

@@ -445,11 +445,6 @@ class DOMNode(MessagePump):
         """The children which don't have display: none set."""
         return [child for child in self.children if child.display]
 
-    def detach(self) -> None:
-        if self._parent and isinstance(self._parent, DOMNode):
-            self._parent.children._remove(self)
-            self._detach()
-
     def get_pseudo_classes(self) -> Iterable[str]:
         """Get any pseudo classes applicable to this Node, e.g. hover, focus.
 

src/textual/message_pump.py

@@ -130,10 +130,6 @@ class MessagePump(metaclass=MessagePumpMeta):
         """
         self._parent = parent
 
-    def _detach(self) -> None:
-        """Unset the parent, removing it from the tree."""
-        self._parent = None
-
     def check_message_enabled(self, message: Message) -> bool:
         return type(message) not in self._disabled_messages
 

tests/test_screens.py

@@ -64,6 +64,16 @@ async def test_screens():
     assert app.screen is screen2
     assert app.screen_stack == [screen2]
 
+    # Uninstall screens
+    app.uninstall_screen(screen1)
+    assert not app.is_screen_installed(screen1)
+    app.uninstall_screen("screen3")
+    assert not app.is_screen_installed(screen1)
+
+    # Check we can't uninstall a screen on the stack
+    with pytest.raises(ScreenStackError):
+        app.uninstall_screen(screen2)
+
     # Check we can't pop last screen
     with pytest.raises(ScreenStackError):
         app.pop_screen()