Order of QDialogButtonBox in .ui file affects initial focus of dialog

The order that a QDialogButtonBox element appears in a UI file affects what controls get initial focus when a dialog is launched. According to documentation, the first control in the Tab order should get the focus. If QDialogButtonBox is the first element listed in the UI file, it receives the focus instead.

I have attached a QtCreator app that demonstrates the problem. It was reproduced on Windows.