Fix bug of window closing and reshowing

Sine Striker

2024-02-23 6c0043c1e3d97398828fbd56448f1cd8ee201e66

 examples/mainwindow/mainwindow.qrc

@@ -1,5 +1,6 @@
<RCC>
    <qresource prefix="/">
        <file>dark-style.qss</file>
        <file>light-style.qss</file>
    </qresource>
</RCC>