Fix window visibility inconsistency

Sine Striker

2023-12-26 1740ed5e0e765ebd8676733243eb3eaa81f95df1

 examples/mainwindow/mainwindow.h

@@ -28,6 +28,7 @@

private:
    void installWindowAgent();
    void installStyleAgent();
    void loadStyleSheet(Theme theme);

    Theme currentTheme{};