QMessageBox static methods do not give focus to popup when activated from keyboard

When using the static methods in QMessageBox (information, question, etc.) to get a pop-up, I get inconsistent behaviour with focus, depending on the type of input triggering the pop-up.
Clicking gives focus to the pop-up, while keyboard input does not.

Steps to reproduce:

• Create a default widget
• Add a lineEdit and a button
• Add slots for returnPressed and clicked using a static method, e.g.,

  QMessageBox::question(this,"Test","Do I have focus?",QMessageBox::Yes|QMessageBox::No);

• Compile and run
• Click the button: the popup has focus
• Press Enter in the line edit: the popup doesn't have focus

Activating the button using the spacebar also does not give focus to the popup, so it does not seem to come from the type of element or the type of slot.