fixed_size for floating windows

[Resonanz]

This seems so basic that I should not need to ask it. Nevertheless...

Why does this code not set the window to the defined fixed_size?

egui::Window::new("My Window")
    .fixed_size([400.0, 400.0])
    .show(ctx, |ui| {
        ui.label("Hello World!");
    });

Surely this explicitly states "fixed_size". I cannot think of a more clear and explicit way of stating something, but it doesn't create a fixed_size window. What am I missing?

egui docs state that fixed_size "Sets the window size and prevents it from being resized by dragging its edges."

But it doesn't do this. Is it a bug?

Ditto for this code. It also does not do what it explicitly says it should:

egui::Window::new("My Window")
    .fixed_rect(egui::Rect::from_min_size(
        egui::pos2(100.0, 100.0), // Window position
        egui::vec2(200.0, 200.0), // Fixed size
    ))
    .show(ctx, |ui| {
        ui.label("Hello World!");
    });

In fact, it's even worse than suggested. By defining the fixed_size to 200.0 x 200.0 then over filling it with text, the window seems to clamp to 200 wide but the height just expands to fit all the text. e.g. it expands well beyond the "fixed_size" and on right outside of the viewport.