fix focus glitch

docs/getting_started.md

@@ -25,13 +25,13 @@ You can install Textual via PyPI.
 If you plan on developing Textual apps, then you should install `textual[dev]`. The `[dev]` part installs a few extra dependencies for development.
 
 ```
-pip install "textual[dev]==0.2.0b6"
+pip install "textual[dev]==0.2.0b7"
 ```
 
 If you only plan on _running_ Textual apps, then you can drop the `[dev]` part:
 
 ```
-pip install textual==0.2.0b6
+pip install textual==0.2.0b7
 ```
 
 !!! important

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "textual"
-version = "0.2.0b6"
+version = "0.2.0b7"
 homepage = "https://github.com/Textualize/textual"
 description = "Modern Text User Interface framework"
 authors = ["Will McGugan <will@textualize.io>"]

src/textual/widget.py

@@ -1850,7 +1850,10 @@ class Widget(DOMNode):
 
         def set_focus(widget: Widget):
             """Callback to set the focus."""
-            widget.screen.set_focus(self, scroll_visible=scroll_visible)
+            try:
+                widget.screen.set_focus(self, scroll_visible=scroll_visible)
+            except NoScreen:
+                pass
 
         self.app.call_later(set_focus, self)