QTreeWidget keyPressEvent

I am using QTreeWidget in an QStackedWidget.Only there is a TreeWidget in one of the pages.
I created keyPressEvent and keyReleaseEvent.When I pressed one of the "Enter-Up-Space-Down" keys I cant use them in keyPressEvent but I can use in keyRelaseEvent.How can control this?Or How can use these keys?

Exactly how did you reimplement keyPressEvent()? Does the function signature match exactly QWidget::keyPressEvent()?

Yes exactly the same implementation.
void keyPressEvent(QKeyEvent *event):

->We get the other keys except the above list.

Do you have any event filters installed? Could you paste the relevant code?