I am developing an application in QT4 but I have a problem still not solving.
I hope someone can help me.

My app UI have a QTabwidget and inside tabwidget, there is a Qwidget. But when I open the app, the Title bar of QWidget display under the Title bar of mainwindow.
Currently, I don't know how to remove or hide that title bar. I found some solution but they didn't work such as window.setWindowFlags(Qt::Window | Qt::FramelessWindowHint);

The screen like as below: