QDialog: Placement and size

I have a custon widget inherited from QDialog, which is modal and displayed on top of current widget.

Note dialog is painted correnctly, but when orientation is changed the size is not updated

In landscape mode the dialog is as width the screen is, should it be from the left to the border of CBAs?

If it is bug, the the following workaround fixes that:

QSize MyDialog::sizeHint() const
{
return QSize(width(), heightForWidth(width()));
}