Dev containers do not have built-in plugins

[sgraband]

Bug Description:

Currently dev containers are started without the built-in plugins of the "parent" application (e.g. Theia IDE).
This leads to the application behaving differently than outside of the dev container, for example the syntax highlighting is missing.
I do not think, that the creator of the devcontainer.json file should be responsible for specifying the built-in plugins, as one would expect that they are "part of the application".

Steps to Reproduce:

1. Open a dev container
2. Observe that there are no built-in plugins displayed in the extension view
3. Check that plugins are not installed (e.g. settings page, no syntax highlighting, etc..)

Additional Information

• Operating System: Ubuntu 22.04
• Theia Version: Theia IDE 1.53.100

[msujew]

Note that this works in the Theia Dev Electron app:

@sgraband What application have you been using to replicate this? I was able to replicate it using the latest TheiaIDE.

See also #13369.

[sgraband]

Thanks for the fast reply. I replicated it with Theia IDE 1.53.100 as well(also updated the ticket).

I will take a detailed look at the PR you linked in a minute, but would you expect this to work automatically with any product or are there some requirements on the products side to configure this/install the plugins in a certain way?

[msujew]

It might be that the localDir call here behaves somehow unexpected in a packaged environment. Generally, there is no configuration necessary for this feature to work.