In my rather complex app, I create several QmainWindows, which show/hide depending on conditions. To make their behavior more deterministic, I want to set their position using setPosition(). The problem is that QMainWindow is not derived from QWindow, as I assumed. So, it has no setPosition(). My questions:
Why QMainWindow is not derived from QWindow? (Just my curiosity)
How can I set the position of a QMainWindow?
(@Tarod and @AlexanderVX already gave the answers in the comment, but here they are again)
Why QMainWindow is not derived from QWindow?
Mainly because QMainWindow existed long before QWindow was invented.
QMainWindow inherits QWidget. QWidget is flexible; it can become a top-level window, or it can become part of a larger widget. This means you can put QMainWindow inside another widget (but you probably don't want to do that).
How can I set the position of a QMainWindow?
The same way you set the position of any other QWidget: http://doc.qt.io/qt-5/qwidget.html#pos-prop (QWidget::move())