As the previous posts explain, you have to use the enter/leave events within the Button Class, so you have to create a custom class inheriting from QAbstractButton. What you have done so far, was to implement the enter-, leaveEvents of the dialog class. They have nothing to do with the buttons. If you are reluctant to introducing your own button class, there is a simpler solution that is more than sufficient for this task: Installing an event filter with QObject::installEventFilter() ...

check the Qt-Docs for this. It's fairly simple.