Dynamic resizing of the QMainWindow does not work appropriately

It would be nice if the auto-resizing feature of a QDialog that occurs when objects are setVisible(true), worked the same way on QMainWindow.

Example:
If the widget is set to be visible (using setVisible(true)) it is visible on the Main Window.
If the widget is set to be invisible (using setVisible(false)) it is disappeared and Main Window has to reduce its height on the height of the invisible widget.

Got instead:
The widget was set to be invisible so it was disappeared but the Main Window did not reduce its dimensions as it was expected.