How to debug QGroundControl in QTCreator

Today I tried to to debug QGroundControl in QTCreator 5.12.
So I set breakpoints in main function and run Debugger, but
QGroundControl didn’t stop in main function and display its main win,dow.
How to debug QGroundControl in QTCreator?

That is pretty much how you do it.

Even after I discovered and learned the function of QtCreator’s debugging buttons (F5, F9, F10, F11…) here, I was unable to start debugging the QGC code for a while because I had no idea of “What to Debug.”
As I read this article ‘How to Debug’, I finally put a breakpoint on the QGC 4.2 source code (F9), started debugging (F5), and proceeded one line at a time (F10).

I don’t know what happened two years ago, but my first debugging experience showed that
after passing the app->exec(); 421 line with code, the main window of the QGC appeared.

Thank you for guiding me to my first debugging experience.