optimize screen composing

Author: willmcgugan

src/textual/dom.py

@@ -1729,7 +1729,7 @@ def _update_styles(self) -> None:
 
         Should be called whenever CSS classes / pseudo classes change.
         """
-        if not self.is_attached:
+        if not self.is_attached or not self.screen.is_mounted:
             return
         try:
             self.app.update_styles(self)

src/textual/screen.py

@@ -1354,6 +1354,10 @@ def _on_screen_resume(self) -> None:
             self._refresh_layout(size)
             self.refresh()
 
+    async def _compose(self) -> None:
+        await super()._compose()
+        self._update_auto_focus()
+
     def _update_auto_focus(self) -> None:
         """Update auto focus."""
         if self.app.app_focus:

src/textual/widgets/_text_area.py

@@ -1782,12 +1782,14 @@ def _restart_blink(self) -> None:
         """Reset the cursor blink timer."""
         if self.cursor_blink:
             self._cursor_visible = True
-            self.blink_timer.reset()
+            if self.is_mounted:
+                self.blink_timer.reset()
 
     def _pause_blink(self, visible: bool = True) -> None:
         """Pause the cursor blinking but ensure it stays visible."""
         self._cursor_visible = visible
-        self.blink_timer.pause()
+        if self.is_mounted:
+            self.blink_timer.pause()
 
     async def _on_mouse_down(self, event: events.MouseDown) -> None:
         """Update the cursor position, and begin a selection using the mouse."""