egui_extras::Table doesn't behave properly when inside of a ScrollArea

[abey79]

Bug

egui_table_bug.mp4

Repro

#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release

use eframe::egui;
use eframe::egui::ScrollArea;

fn main() -> Result<(), eframe::Error> {
    env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
    let options = eframe::NativeOptions {
        viewport: egui::ViewportBuilder::default().with_inner_size([320.0, 240.0]),
        ..Default::default()
    };
    eframe::run_native(
        "My egui App",
        options,
        Box::new(|cc| {
            // This gives us image support:
            egui_extras::install_image_loaders(&cc.egui_ctx);

            Box::<MyApp>::default()
        }),
    )
}

#[derive(Default)]
struct MyApp;

impl eframe::App for MyApp {
    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
        egui::CentralPanel::default().show(ctx, |ui| {
            ScrollArea::both().show(ui, |ui| {
                egui_extras::TableBuilder::new(ui)
                    .auto_shrink([false, true])
                    .vscroll(false)
                    .columns(egui_extras::Column::exact(50.0), 2)
                    .header(18.0, |mut header| {
                        header.col(|ui| {
                            ui.label("Col1");
                        });
                        header.col(|ui| {
                            ui.label("col2");
                        });
                    })
                    .body(|body| {
                        body.rows(18.0, 100, |idx, mut row| {
                            row.col(|ui| {
                                ui.label(format!("R{}C1", idx));
                            });
                            row.col(|ui| {
                                ui.label(format!("R{}C2", idx));
                            });
                        });
                    });
            });
        });
    }
}

[Imberflur]

I think I may have a similar bug. My table is inside a scroll arena (at the bottom of that area) and when using body.rows() only a single row is displayed. However, when adding the rows individually with body.row() everything seems to work well. IIUC rows is more performant because it can avoid work for rows that aren't visible. Maybe this issue is related to that logic?