Some progress. I have tried to manually build the app from source, works. fine. Tried with release-1.2.6, pre-release 1.3.9 and dev. The problem seems to occur after this command:
$ npm run dist
None of the binaries (even unpacked) works after that command. All leading to the white frame without any response. I can reproduce this across various version.
Oh, and if I run it as a flatpak, it works.
Unfortunately, my foo with the node ecosystem is too weak to come to some conclusion.
Works:
$ npm install --cache ./npm-cache
$ cd ElectronClient
$ npm install --cache ./npm-cache
$ npm start
Doesn't work:
$ npm install --cache ./npm-cache
$ cd ElectronClient
$ npm install --cache ./npm-cache
$ npm run dist
$ cd dist
$ chmod +x Joplin-x.x.x.AppImage
$ ./Joplin-x.x.x.AppImage