Improve fixed width/height/size hit testing

Zhao Yuhang

2024-05-23 6002cd46a2c5a1c2c4afdbf8e491e76f68b9bfd8

 examples/mainwindow/mainwindow.h

@@ -30,6 +30,8 @@
protected:
    bool event(QEvent *event) override;

    void closeEvent(QCloseEvent *event) override;

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