This answer to this question is as found here: Python PySide (Internal c++ Object Already Deleted) Apparently, assigning one widget to QMainWindow using setCentralWidget and then assigning another widget with setCentralWidget will cause the underlying c++ QWidget to be deleted, even though I have an object that maintains reference to it. Note: QMainWindow takes ownership … Read more
You can have as many QMainWindow instances as you want. A QMainWindow is just a QWidget which provides a menu bar, toolbar, status bar and docking framework. But basically it is just a QWidget so you can have as many as you like. Normally you only have a single QMainWindow for GUI design reasons since … Read more
Somewhere in your QMainWindow constructor, do this: resize(QDesktopWidget().availableGeometry(this).size() * 0.7); This will resize the window to 70% of the available screen space.
The method is setWindowTitle(): setWindowTitle(const QString &) http://doc.qt.io/qt-4.8/qwidget.html#windowTitle-prop