optional actions

Author: willmcgugan

src/textual/demo.css

@@ -29,7 +29,7 @@ Sidebar {
 }
 
 Sidebar:focus-within {
-    offset: 0 0 !important;    
+    offset: 0 0 !important;        
 }
 
 Sidebar.-hidden {

src/textual/screen.py

@@ -295,22 +295,19 @@ def set_focus(self, widget: Widget | None, scroll_visible: bool = True) -> None:
             # No focus, so blur currently focused widget if it exists
             if self.focused is not None:
                 self.focused.post_message_no_wait(events.Blur(self))
-                self.focused.emit_no_wait(events.DescendantBlur(self))
                 self.focused = None
             self.log.debug("focus was removed")
         elif widget.can_focus:
             if self.focused != widget:
                 if self.focused is not None:
                     # Blur currently focused widget
                     self.focused.post_message_no_wait(events.Blur(self))
-                    self.focused.emit_no_wait(events.DescendantBlur(self))
                 # Change focus
                 self.focused = widget
                 # Send focus event
                 if scroll_visible:
                     self.screen.scroll_to_widget(widget)
                 widget.post_message_no_wait(events.Focus(self))
-                widget.emit_no_wait(events.DescendantFocus(self))
                 self.log.debug(widget, "was focused")
 
     async def _on_idle(self, event: events.Idle) -> None:

src/textual/widget.py

@@ -2344,17 +2344,22 @@ def _on_enter(self, event: events.Enter) -> None:
         self.mouse_over = True
 
     def _on_focus(self, event: events.Focus) -> None:
-        for node in self.ancestors_with_self:
-            if node._has_focus_within:
-                self.app.update_styles(node)
         self.has_focus = True
         self.refresh()
+        self.emit_no_wait(events.DescendantFocus(self))
 
     def _on_blur(self, event: events.Blur) -> None:
-        if any(node._has_focus_within for node in self.ancestors_with_self):
-            self.app.update_styles(self)
         self.has_focus = False
         self.refresh()
+        self.emit_no_wait(events.DescendantBlur(self))
+
+    def _on_descendant_blur(self, event: events.DescendantBlur) -> None:
+        if self._has_focus_within:
+            self.app.update_styles(self)
+
+    def _on_descendant_focus(self, event: events.DescendantBlur) -> None:
+        if self._has_focus_within:
+            self.app.update_styles(self)
 
     def _on_mouse_scroll_down(self, event) -> None:
         if self.allow_vertical_scroll:
@@ -2398,34 +2403,42 @@ def _on_hide(self, event: events.Hide) -> None:
     def _on_scroll_to_region(self, message: messages.ScrollToRegion) -> None:
         self.scroll_to_region(message.region, animate=True)
 
-    def action_scroll_home(self) -> None:
-        if self._allow_scroll:
-            self.scroll_home()
-
-    def action_scroll_end(self) -> None:
-        if self._allow_scroll:
-            self.scroll_end()
-
-    def action_scroll_left(self) -> None:
-        if self.allow_horizontal_scroll:
-            self.scroll_left()
-
-    def action_scroll_right(self) -> None:
-        if self.allow_horizontal_scroll:
-            self.scroll_right()
-
-    def action_scroll_up(self) -> None:
-        if self.allow_vertical_scroll:
-            self.scroll_up()
-
-    def action_scroll_down(self) -> None:
-        if self.allow_vertical_scroll:
-            self.scroll_down()
-
-    def action_page_down(self) -> None:
-        if self.allow_vertical_scroll:
-            self.scroll_page_down()
-
-    def action_page_up(self) -> None:
-        if self.allow_vertical_scroll:
-            self.scroll_page_up()
+    def action_scroll_home(self) -> bool | None:
+        if not self._allow_scroll:
+            return False
+        self.scroll_home()
+
+    def action_scroll_end(self) -> bool | None:
+        if not self._allow_scroll:
+            return False
+        self.scroll_end()
+
+    def action_scroll_left(self) -> bool | None:
+        if not self.allow_horizontal_scroll:
+            return False
+        self.scroll_left()
+
+    def action_scroll_right(self) -> bool | None:
+        if not self.allow_horizontal_scroll:
+            return False
+        self.scroll_right()
+
+    def action_scroll_up(self) -> bool | None:
+        if not self.allow_vertical_scroll:
+            return False
+        self.scroll_up()
+
+    def action_scroll_down(self) -> bool | None:
+        if not self.allow_vertical_scroll:
+            return False
+        self.scroll_down()
+
+    def action_page_down(self) -> bool | None:
+        if not self.allow_vertical_scroll:
+            return False
+        self.scroll_page_down()
+
+    def action_page_up(self) -> bool | None:
+        if not self.allow_vertical_scroll:
+            return False
+        self.scroll_page_up()