Fixes issue #1249.
In Qt5, delta() method of the QWheelEvent is deprecated. pixelDelta() or angleDelta() should be used. Details: https://doc.qt.io/qt-5/qwheelevent-obsolete.html
In Qt5, delta() method of the QWheelEvent is deprecated. pixelDelta() or angleDelta() should be used. Details: https://doc.qt.io/qt-5/qwheelevent-obsolete.html