Window Transparency not working

[Airyzz]

I am currently testing latest commit in master (ba5abfc) and window transparency no longer works:

Testing the same code but using commit b0f000d it works fine. I think it was introduced in 3159dd1

use speedy2d::color::Color;
use speedy2d::dimen::Vector2;
use speedy2d::window::{WindowCreationOptions, WindowHandler, WindowHelper};
use speedy2d::{Graphics2D, Window};

fn main() {
    let window = Window::new_with_options(
        "Title",
        WindowCreationOptions::new_windowed(
            speedy2d::window::WindowSize::PhysicalPixels(Vector2::new(500, 500)),
            None,
        )
        .with_always_on_top(true)
        .with_transparent(true),
    )
    .unwrap();
    window.run_loop(MyWindowHandler {});
}

struct MyWindowHandler {}

impl WindowHandler for MyWindowHandler {
    fn on_draw(&mut self, helper: &mut WindowHelper, graphics: &mut Graphics2D) {
        graphics.clear_screen(Color::from_rgba(0.0, 0.0, 0.0, 0.0));
        graphics.draw_circle((100.0, 100.0), 75.0, Color::BLUE);
        helper.request_redraw();
    }
}