I have added the icon of the app in the main.cpp as follows:

MainWindow w; w.setWindowIcon(QIcon(":/images/logo.png"));

The icon can show up in the taskbar when app is running. But the icon is missing in the pop-up menu, when I right click on the app. The issue is shown in the the image:

Adding this line in the mainwindow.cpp does not work either:

setWindowIcon(QIcon(":/images/logo.png"));

Anything that I am missing in the Qt 6 C++ code? Thanks.