Unfortunately, it doesn't seems to work... actions() returns me an empty list. I think I'll go for QTextEdit::createMimeDataFromSelection() because otherwise I won't be able to deal with drag & drop (I didn't think about it :/ ) Thanks anyway!

With Qt, you usually trigger a signal when conditions are met that you connect to the setEnable of the QAction you want. Or you modify the action object directly.

Well, I have a custom shortcut shC applied to Action/Menu which is global (in every window), but I can not register that into window A, or window B. I mean, I am on OS X, where there is only one menubar that is shared across the multiple windows, so I have to dispatch them, right? I mean, for example, Qt Creator has a shortcut "Run" which is invokable from many windows. But I can not make two menubars and/or having two actions, right?

@Harry123 I did it putting this in main.cpp and that's all folks ;-) QApplication a(argc, argv); a.setStyle("fusion");

Hi SGaist, Thanks for your reply. I don't think it caused by missing QWidget::addAction, because sometimes the shortcuts works well. I've used the default shortcuts of widget(copy, paste and cut). It's strange that after the child window lunched the shortcuts don't work, but after click the Main window's menu bar(even the button in menu is disabled), the shortcuts works well. So i suspected whether there is the shortcut focus.

Yes, you are correct. There is more information here for anyone else interested: https://bugreports.qt.io/browse/QTBUG-47701