The latest official WindowBuilder P2 update site I know of is located here. If you use this update site to install WindowBuilder into Eclipse Neon you will encounter an error.

Background information

The version of this P2 update sites features and plugins is 1.8.0.r45x201506110827:

When running WindowBuilder version 1.8.0.r45x201506110827 under Eclipse Neon you will get the following error:

Currently there is no WindowBuilder P2 update for Eclipse Neon. See here and here for more background information.

Solution

Luckily Lars Vogel stepped up and made some contribution to the project to enable headless Maven Tycho builds. Therefore it is easy to build a WindowBuilder Pro update site yourself:

1. Clone the WindowBuilder project from https://git.eclipse.org/r/windowbuilder/org.eclipse.windowbuilder.
2. Change to org.eclipse.windowbuilder and run mvn verify.
3. The P2 update site will be located under org.eclipse.wb.releng.updatesite/target/repository.

Just be sure to use at least Maven version 3.3.9. When using Maven version 3.3.3 the build failed with the following error message:

<...>
ERROR: Failed to parse POMs
org.apache.maven.project.ProjectBuildingException: Some problems were encountered while processing the POMs:
[ERROR] Child module /appl/jenkins_home/workspace/org.eclipse.windowbuilder/org.eclipse.wb.core/pom.xml of /appl/jenkins_home/workspace/org.eclipse.windowbuilder/pom.xml does not exist @
[ERROR] Child module /appl/jenkins_home/workspace/org.eclipse.windowbuilder/org.eclipse.wb.core.databinding/pom.xml of /appl/jenkins_home/workspace/org.eclipse.windowbuilder/pom.xml does not exist @

The features and plugins of this P2 update site will have version 1.9.0:

Using my unoffical P2 update site

If you don’t want to build and serve the P2 update site yourself you can use my P2 update site located at https://dl.bintray.com/zaunerc/p2/org.eclipse.windowbuilder.p2_site/latest/. Currently commit c4e0ead9dde1c8c64116c921f9d7b63cb2d4a54a is served. The WindowBuilder source code repo is currently not mirred to GitHub. Therefore if you want to get a quick overview about the latest commits you can use the Git web frontend over at eclipse.org.

Further notes

If you want to use WindowBuilder to work on SWT components it is sufficient to install the following features:

• org.eclipse.wb.rcp.feature.feature.group
• org.eclipse.wb.rcp.doc.user.feature.feature.group
• org.eclipse.wb.doc.user.feature.feature.group

Other WindowBuilder blog posts / Eclipse plugins which might interest you

• Eclipse WindowBuilder: JavaDoc tags reference
• Eclipse WindowBuilder documentation
• Eclipse Runner Plugin (Disclaimer: I am the current maintainer)

Update #1 (25. July 2016)

The WindowBuilder project itself now provides an integration build of WindowBuilder for Eclipse Neon. You can monitor progress of the re-introduction of WindowBuilder into Neon.1 here. Thanks to StackOverflow user Mickael for providing this info.