https://forum.qt.io/topic/19036/qmainwindow-with-qdockwidget-or-some-type-of-sides
QMainWindow with QDockWidget or some type of sides? | Qt Forum
Aug 13, 2012 - I am making a print preview kind of page and want to have some type of different colored sides so the page doesnt take up the whole Window so itll look kind ...
qmainwindowtypesidesqtforum
https://doc.qt.io/qt-6.8/qmainwindow.html
QMainWindow Class | Qt Widgets 6.8.7
The QMainWindow class provides a main application window.
qmainwindowclassqtwidgets