Difference between returning false and calling parent's eventFilter to propagate the event

Question

I have a class inherited from QDialog that implements eventFilter to log some events. After logging the event I want to pass it later. What's the difference between return false; and return QDialog::eventFilter(obj, event); at this point? I've seen both options used in Qt examples.

Answer 1

The Qt documentation says, that

... unhandled events are passed to the base class's eventFilter() function, since the base class might have reimplemented eventFilter() for its own internal purposes.

i.e. if you handle an event in your event filter, you should either return true or false, the rest of events should be propagated to the parent class, because it might implement its own filter too.