[MacOS] Table is rendered incompletely on mouse-down

[basilevs]

Describe the bug
Table repaint triggered from selection listener of another control is rendered incompletely while mouse button is held.

To Reproduce

/*******************************************************************************
 * Copyright (c) 2026 Vasili Guelvich and others
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *******************************************************************************/
package org.eclipse.swt.snippets;

/*
 * Table example: repaint triggered from selection listener of another control.
 *
 * Demonstrates a bug where table repaint is rendered incompletely while the
 * mouse button is held down. Click and hold items in the left list and observe
 * the right table.
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 *
 * @see <a href="https://github.com/eclipse-platform/eclipse.platform.swt/issues/3311">Issue 3311</a>
 */
import org.eclipse.swt.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public class Snippet395 {

	public static void main(String[] args) {
		Display display = new Display();
		Shell shell = new Shell(display);
		shell.setText("Table SetInput on Selection - Bug 3311");
		shell.setMinimumSize(300, 300);
		shell.setLayout(new FillLayout());

		String[][] data = {
			{"1 very long long long long long long string 1", "2 very long long long long long long string 2"},
			{"1 short string 1", "2 short string 2"},
			{"3 short string 4", "4 short string 5"}
		};
		String[] labels = {"long values", "short values", "2 short values 2"};
		String[][] currentData = {null};

		List selector = new List(shell, SWT.BORDER | SWT.SINGLE);
		selector.setItems(labels);

		Table table = new Table(shell, SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER | SWT.VIRTUAL | SWT.FULL_SELECTION);

		table.addListener(SWT.SetData, event -> {
			TableItem ti = (TableItem) event.item;
			int index = table.indexOf(ti);
			if (currentData[0] != null && index < currentData[0].length) {
				ti.setText(currentData[0][index]);
			}
		});

		selector.addListener(SWT.Selection, event -> {
			display.asyncExec(() -> {
				if (table.isDisposed()) return;
				try {
					table.setRedraw(false);
					int index = selector.getSelectionIndex();
					currentData[0] = index >= 0 ? data[index] : null;
					table.setItemCount(currentData[0] != null ? currentData[0].length : 0);
					table.clearAll();
				} finally {
					table.setRedraw(true);
				}
			});
		});

		shell.setSize(400, 300);
		shell.open();
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch()) {
				display.sleep();
			}
		}
		display.dispose();
	}

}

• Click every item in left pane a few times
• Click and hold every item in left pane, observe right pane
• Try click-and-hold second (middle) item multiple times

Expected behavior
All items are rendered the mouse button is pushed, nothing happens when button is released.

Observed behavior
Right pane renders random prefixes of data. Lines have incomplete/truncated symbols at the end.
Rendering completes when mouse button is released.

Screenshots

Screen.Recording.2026-05-16.at.16.18.37.mov

Environment:

1. Select the platform(s) on which the behavior is seen:

• • All OS
• • Windows
• • Linux
• • macOS

2. Additional OS info (e.g. OS version, Linux Desktop, etc)
   MacOS: 26.4.1 (25E253)

3. JRE/JDK version

openjdk 21.0.10 2026-01-20 LTS
OpenJDK Runtime Environment Temurin-21.0.10+7 (build 21.0.10+7-LTS)
OpenJDK 64-Bit Server VM Temurin-21.0.10+7 (build 21.0.10+7-LTS, mixed mode, sharing)
otool -l /Library/Java/JavaVirtualMachines/temurin-21.jdk/Contents/Home/bin/java | grep sdk
      sdk 14.4

Version since
Unknown

Workaround (or) Additional context
Originally found in #3260
Reproduces more consistently with eGit

[tmssngr]

Would you mind providing a pure SWT snippet without the use of JFace?

[basilevs]

Would you mind providing a pure SWT snippet without the use of JFace?

Updated

[tmssngr]

Could you please add the [macOS] prefix to the title?

What exactly do you expect to happen when pressing the mouse button? Do you expect the selection event being sent on mouse-down instead of mouse-up?

[basilevs]

What exactly do you expect to happen when pressing the mouse button? Do you expect the selection event being sent on mouse-down instead of mouse-up?

The problem is not the selection event (which is already sent on mouse-down). The problem is rendering defect in the right pane - the text is rendered partially. See video on 53 second position