This behaviour is still not documented (Qt Bug Tracker). The special modifier handling is implemented in QWindowsPointerHandler::translateMouseWheelEvent. A WM_MOUSEWHEEL event is treated like a WM_MOUSEHWHEEL event: const QPoint angleDelta = (msg.message == WM_MOUSEHWHEEL || (keyModifiers & Qt::AltModifier)) ? QPoint(delta, 0) : QPoint(0, delta);

@SGaist Hi thank you, I have call a class to update it: MainWidget::getInstance()->AllViewsUpdate(true);