added borders utility

src/textual/devtools/borders.py

@@ -0,0 +1,70 @@
+from textual.app import App, ComposeResult
+from textual.constants import BORDERS
+from textual.widgets import Button, Static
+from textual import layout
+
+
+TEXT = """I must not fear.
+Fear is the mind-killer.
+Fear is the little-death that brings total obliteration.
+I will face my fear.
+I will permit it to pass over me and through me.
+And when it has gone past, I will turn the inner eye to see its path.
+Where the fear has gone there will be nothing. Only I will remain."""
+
+
+class BorderButtons(layout.Vertical):
+    CSS = """
+    BorderButtons {
+        dock: left;
+        width: 20;
+    }
+
+    BorderButtons > Button {
+        width: 20;
+    }
+    """
+
+    def compose(self) -> ComposeResult:
+        for border in BORDERS:
+            if border:
+                yield Button(border, id=border)
+
+
+class BorderApp(App):
+    """Displays a pride flag."""
+
+    COLORS = ["red", "orange", "yellow", "green", "blue", "purple"]
+
+    CSS = """
+    Screen {
+        background: $surface;
+    }
+    Static {
+        margin: 2 4;
+        padding: 2 4;
+        border: solid $warning;
+        height: auto;
+        background: $panel;
+        color: $text-panel-fade-1;
+    }
+    """
+
+    def compose(self):
+        self.dark = True
+        yield BorderButtons()
+        self.text = Static(TEXT)
+        yield self.text
+
+    def handle_pressed(self, event):
+        self.text.styles.border = (
+            event.button.id,
+            self.stylesheet.variables["warning"],
+        )
+        self.bell()
+
+
+app = BorderApp()
+
+if __name__ == "__main__":
+    app.run()

src/textual/widgets/_button.py

@@ -192,15 +192,19 @@ class Button(Widget, can_focus=True):
         if self.disabled:
             return
         # Manage the "active" effect:
+        self._start_active_affect()
+        # ...and let other components know that we've just been clicked:
+        await self.emit(Button.Pressed(self))
+
+    def _start_active_affect(self) -> None:
         self.add_class("-active")
         self.set_timer(
             self.ACTIVE_EFFECT_DURATION, partial(self.remove_class, "-active")
         )
-        # ...and let other components know that we've just been clicked:
-        await self.emit(Button.Pressed(self))
 
     async def on_key(self, event: events.Key) -> None:
         if event.key == "enter" and not self.disabled:
+            self._start_active_affect()
             await self.emit(Button.Pressed(self))
 
     @classmethod