egui_resizing_issue.rs

use eframe::{
    egui::{self, Color32, Vec2},
    epi,
};

#[derive(Default)]
struct UiApp {}

impl epi::App for UiApp {
    fn name(&self) -> &str {
        "An App"
    }

    fn setup(
        &mut self,
        _ctx: &egui::Context,
        _frame: &epi::Frame,
        _storage: Option<&dyn epi::Storage>,
    ) {
    }

    fn update(&mut self, ctx: &egui::Context, _frame: &epi::Frame) {
        egui::CentralPanel::default().show(ctx, |ui| {
            // Set the x value to something excessively high
            ui.style_mut().spacing.item_spacing = Vec2::new(80., 3.);

            ui.vertical_centered_justified(|ui| {
                egui::ScrollArea::vertical().show(ui, |ui| {
                    for _ in 0..10 {
                        // Frame is for visualization purposes, not needed
                        egui::Frame {
                            fill: Color32::DARK_GRAY,
                            ..Default::default()
                        }
                        .show(ui, |ui| {
                            ui.set_height(20.);

                            ui.centered_and_justified(|ui| {
                                ui.label("Fill");
                            });
                        });
                    }
                });
            });
        });
    }
}

fn main() {
    let app = UiApp::default();
    let native_options = eframe::NativeOptions::default();
    eframe::run_native(Box::new(app), native_options);
}