Why the Slider doesn't get centered when using Layout::top_down(Align::Center) but a Label does?

[LaBatata101]

Here's the relevant part of the code. How can I center the Slider?

impl eframe::epi::App for MyApp {
    fn update(&mut self, ctx: &egui::CtxRef, _frame: &eframe::epi::Frame) {
        egui::CentralPanel::default().show(ctx, |ui| {
            ui.with_layout(Layout::top_down(Align::Center), |ui| {
                ui.add(Label::new("test"));
                ui.add(
                    Slider::new(&mut self.value, 0..=3600).show_value(true)
                );
            });
        });
    }

    fn name(&self) -> &str {
        "Test egui"
    }
}

[emilk]

You can't - the slider is not an atomic widget (it contains many smaller widgets in it). It is a fundamental drawback of single-pass immediate mode GUI:s, and won't be solved until #843 is addressed

[Dominik1999]

I assume this is still an issue? Or is it possible to center a set of widgets within the CentralPanel?

        egui::CentralPanel::default()
            .show(ctx, |ui| {
            // The central panel the region left after adding TopPanel's and SidePanel's
            ui.vertical_centered(|ui| {
                ui.heading("The Game of Life Universe");
            });

            // somehow it doesn't work to center the grid
            // seems impossible, https://github.com/emilk/egui/discussions/1144
            ui.vertical_centered(|ui| {
                egui::Grid::new("some_unique_id").show(ui, |ui| {
                    for i in 0..=*(sqrt_number_of_cells) as usize  - 1 { 
                        for j in 0..=*(sqrt_number_of_cells) as usize - 1 { 
                            ui.add(custom_checkbox(&mut self.front_end_grid[i][j]));       
                        }
                        ui.end_row();
                    }
                });
            });

^^ this code somehow doesn't center the grid. Whatever I do it stays in the corner up left.

[emanuele-em]

I interested in this