JetBrains Runtime Issue with Touch Events on Windows

[dpolivaev]

Dear JetBrains Team,

I develop the open-source mind map editor Freeplane. Recently, I embedded JetBrains Java Runtime into the Windows version due to its better emoji font support. However, during preview testing, a user reported losing touch functionality with their Surface Pro 7, affecting both pen and finger inputs.

To investigate, I wrote a minimal Java app to log mouse events. Testing revealed the following:

• Using Azul Zulu Java Runtime v21.0.5, touch inputs were correctly mapped to mouse events.
• With JetBrains Runtime 21.0.5b509.30 and 21.0.5b631.16, only pure mouse events were logged; no touch events were detected.

The app requires the following Java option:

--add-exports java.desktop/sun.awt=ALL-UNNAMED

This is necessary to access the internal sun.awt APIs, specifically for detecting whether a MouseEvent was caused by a touch event.

Code:

package com.example;

import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.util.logging.Logger;
import sun.awt.AWTAccessor;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class TouchMouseEventExample {
    private static final Logger logger = Logger.getLogger(TouchMouseEventExample.class.getName());
    public static void main(String[] args) {
        logger.info("Java Version: " + System.getProperty("java.version"));
        logger.info("Java Vendor: " + System.getProperty("java.vendor"));
        JFrame frame = new JFrame("Touch Event Simulation");
        JPanel panel = new JPanel();

        panel.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                printEvent(e);
            }

            @Override
            public void mouseReleased(MouseEvent e) {
                printEvent(e);
            }

            @Override
            public void mouseClicked(MouseEvent e) {
                printEvent(e);
            }
        });

        panel.addMouseMotionListener(new MouseMotionAdapter() {
            @Override
            public void mouseDragged(MouseEvent e) {
                printEvent(e);
            }
        });

        frame.add(panel);
        frame.setSize(400, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

    private static void printEvent(MouseEvent e) {
        boolean isCausedByTouchEvent = AWTAccessor.getMouseEventAccessor().isCausedByTouchEvent(e);
        logger.info(e.toString() + "\n"
                + "Modifiers: " + e.getModifiersEx() + (isCausedByTouchEvent ? "caused by Touch Event" : ""));
    }
}

System Details:

• OS: Windows 11 Home, Version 10.0.26100, Italian localization
• Device: Microsoft Surface Pro 7
• CPU: Intel Core i5-1035G4, 4 cores, 8 logical processors

Relationship to Existing Issues:

This issue seems related to the previously reported #467. It demonstrates that the problem is broader and not tied to a specific library. The findings can extend and complement the existing YouTrack issue JBR-7716, created by @vprovodin, to address issue #467.

I kindly request that this issue be given higher priority due to its significant impact on Java applications running on devices with touch input.

Best regards,
Dimitry Polivaev