Probably a consequence of #13831. cc @tsmaeder.

I can reproduce the issue. Something seems to go wrong when handling the command line parameters for the second "instance" (i.e. window). The error is likely located here or at least should be investigated starting from there.

Should be fixed by https://github.com/eclipse-theia/theia/pull/14764/files#diff-9916c8b433323cefe738c0fca755b5f2e7b3a7ef586a39622fb6fa5cf487f410

I can confirm that this is fixed in the Electron example application in the Theia repository. Still should be retested again once we have new Theia IDE build.

@tsmaeder The 1.59.0 preview build does not fix the issue! The second "instance" still opens without an opened directory

@sdirix what command are you using to test this?

Considering it works with the in-repo version of theia, there must be something going on with the handling of cmd-line parameters in the native launcher.

I can confirm that doing

C:\Users\thomas\AppData\Local\Programs\TheiaIDE\TheiaIDE.exe C:\Users\thomas\code\theia\theia5

does not open the theia5 workspace in a second instance.

This is weird, since we're just listening to the 'second-instance' event on the electron app object. The only reason I can think why this should work differently is if the built version of electron somehow sending a different argv with the event. @jfaltermeier are you aware how the Theia executable starts the electron process?

It might be that we're simply running into this problem: electron/electron#4690 (comment)

It's a bit weird how we determine whether the app is packaged in electron-mainapplication.ts. Shouldn't app.isPackaged do exactly what we want?

@jfaltermeier what's the best way to test a fix that only happens in the built version of TheiaIDE?

I think the easiest way is to publish your Theia build to a local npm registry like Verdaccio. This should be roughly how it looks:

In the Theia repository:
npm logout (optional, to ensure you can't accidentally publish to the real registry)
docker pull verdaccio/verdaccio
docker run -it --rm --name verdaccio -p 4873:4873 verdaccio/verdaccio
npm login --registry http://localhost:4873 (you can enter any random credentials)
npm config set registry http://localhost:4873
Run the Theia release script

In the Theia IDE repository:
yarn config set registry http://localhost:4873
Follow https://github.com/eclipse-theia/theia-ide/blob/master/PUBLISHING.md#update-package-versions-and-theia to update to your local Theia version.