What's Changed

• Fix subflow module sending messages to debug sidebar by @knolleary in https://github.com/node-red/node-red/pull/4642
• Guard refresh of unknown subflow by @knolleary in https://github.com/node-red/node-red/pull/4640
• Fix use of spawn on windows with cmd files by @knolleary in https://github.com/node-red/node-red/pull/4652
• Prevent subflow being added to itself by @knolleary in https://github.com/node-red/node-red/pull/4654
• Bump for 3.1.9 release by @knolleary in https://github.com/node-red/node-red/pull/4655

Full Changelog: https://github.com/node-red/node-red/compare/3.1.8...3.1.9