#include <SFML/Graphics.hpp>

int main()
{
    sf::RenderWindow window(sf::VideoMode::getDesktopMode(), "");

    while (window.isOpen())
    {
        sf::Event event;
        while (window.pollEvent(event))
        {
            switch (event.type)
            {
                case sf::Event::Closed:
                    window.close();
                    break;

                case sf::Event::LostFocus:
                    window.setActive(false);
                    break;

                case sf::Event::GainedFocus:
                    window.setActive(true);
                    break;
            }
        }

        window.clear(sf::Color::White);
        window.display();
    }
}