How to receive mouse wheel events with QSystemTrayIcon?

[namako]

Hi everyone.

I am a QT beginner.
I searched for topics using the words "QSystemTrayIcon" and "wheelEvent" from the search bar of this site, but could not find a solution.
Please give me some advice.

I have written a code to receive the mouse wheel event.
However, when the mouse cursor is in the MainWindow, I can receive the wheel event, but when the mouse pointer is in the system tray icon of the application, I cannot receive the event.

Is there any way to fix this?

Thank you.

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QSystemTrayIcon>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow() override;

protected:
    void wheelEvent(QWheelEvent* event) override;

private:
    Ui::MainWindow *ui;

    QSystemTrayIcon* systemTrayIcon;
};

#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>
#include <QTime>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    systemTrayIcon = new QSystemTrayIcon(QIcon(":/tray_icon.png"));
    systemTrayIcon->show();
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::wheelEvent(QWheelEvent *event)
{
    qDebug() << QTime::currentTime();
}

os: Linux Debian 10.10 64bit
Desktop Environment: LXDE
Window Manager: Openbox with lxpanel 0.10.0
QT: Qt 5.11.3
QT Creator: Qt Creator 4.8.2 based on Qt 5.11.3
qmake: QMake version 3.1 Using Qt version 5.11.3

[JoeCFD]

Only on X11, when a tooltip is requested, the QSystemTrayIcon receives a QHelpEvent of type QEvent::ToolTip. Additionally, the QSystemTrayIcon receives wheel events of type QEvent::Wheel. These are not supported on any other platform.
https://doc.qt.io/qt-5/qsystemtrayicon.html#details

[namako]

@JoeCFD Thanks for the reply.
I understand now.
I'll try it soon.
Thank you for your kindness and clear explanation.
(^_^)