diff --git a/egui/src/containers/combo_box.rs b/egui/src/containers/combo_box.rs
index 30bcd200..54795cd3 100644
--- a/egui/src/containers/combo_box.rs
+++ b/egui/src/containers/combo_box.rs
@@ -60,13 +60,10 @@ pub fn combo_box(
                 let frame = Frame::popup(ui.style());
                 let frame_margin = frame.margin;
                 frame.show(ui, |ui| {
-                    ui.with_layout(
-                        Layout::top_down(Align::left()).with_cross_justify(true),
-                        |ui| {
-                            ui.set_min_width(button_response.rect.width() - 2.0 * frame_margin.x);
-                            menu_contents(ui);
-                        },
-                    );
+                    ui.with_layout(Layout::top_down_justified(Align::left()), |ui| {
+                        ui.set_min_width(button_response.rect.width() - 2.0 * frame_margin.x);
+                        menu_contents(ui);
+                    });
                 })
             });
 
diff --git a/egui/src/layout.rs b/egui/src/layout.rs
index 0640a767..ad674212 100644
--- a/egui/src/layout.rs
+++ b/egui/src/layout.rs
@@ -166,6 +166,11 @@ impl Layout {
         }
     }
 
+    /// Top-down layout justifed so that buttons etc fill the full available width.
+    pub fn top_down_justified(cross_align: Align) -> Self {
+        Self::top_down(cross_align).with_cross_justify(true)
+    }
+
     pub fn bottom_up(cross_align: Align) -> Self {
         Self {
             main_dir: Direction::BottomUp,
diff --git a/egui/src/menu.rs b/egui/src/menu.rs
index 46bd1486..2a149aac 100644
--- a/egui/src/menu.rs
+++ b/egui/src/menu.rs
@@ -111,10 +111,7 @@ fn menu_impl<'c>(
                 style.visuals.widgets.inactive.bg_fill = TRANSPARENT;
                 style.visuals.widgets.inactive.bg_stroke = Stroke::none();
                 ui.set_style(style);
-                ui.with_layout(
-                    Layout::top_down(Align::left()).with_cross_justify(true),
-                    add_contents,
-                );
+                ui.with_layout(Layout::top_down_justified(Align::left()), add_contents);
             })
         });