X server: in-container development in VSCode

Question

I'd like to debug a desktop application (notably, this one, based on electron ) using VSCode's in-container feature.

For this purpose, I'm using this dockerfile:

FROM electronuserland/builder:wine-chrome

# Create the user and assign grants
ARG USERNAME=electron
ARG USER_UID=1000
ARG USER_GID=$USER_UID

RUN groupadd --gid $USER_GID $USERNAME \
    && useradd --shell /bin/bash --uid $USER_UID --gid $USER_GID -m $USERNAME \
    && apt-get update \
    && apt-get install -y sudo \
    && echo $USERNAME ALL=\(root\) NOPASSWD:ALL > /etc/sudoers.d/$USERNAME \
    && chmod 0440 /etc/sudoers.d/$USERNAME

USER $USERNAME

With this in place, I can successfully build the application (using sudo npm ci) and create the Windows binaries (using sudo npm run package:windows).

Unfortunately, if I attempt to run a debug session with sudo npm start, I get:

✔ Compiled successfully.
[1023/144902.115440:FATAL:electron_main_delegate.cc(299)] Running as root without --no-sandbox is not supported. See https://crbug.com/638180.
/.../node_modules/electron/dist/electron exited with signal SIGTRAP

On the other hand, if I attempt to run a debug session without sudo, that is, launching npm start, I get this:

✔ Compiled successfully.
[22189:1023/151033.444880:FATAL:setuid_sandbox_host.cc(157)] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I'm aborting now. You need to make sure that /.../node_modules/electron/dist/chrome-sandbox is owned by root and has mode 4755.
/.../node_modules/electron/dist/electron exited with signal SIGTRAP
[22205:0100/000000.493074:ERROR:zygote_linux.cc(661)] write: Broken pipe (32)
ERROR: "electron:serve" exited with 1.

The "start" script in package.json is this:

"start": "npm-run-all -p ng:serve electron:serve",

What configuration is missing (and where!) to make the whole thing work?

NOTES:

• Attempting to apply ownership and grants to chrome-sandbox like this:

  sudo chown root /.../node_modules/electron/dist/chrome-sandbox 
  sudo chmod 4755 /.../node_modules/electron/dist/chrome-sandbox 
  

  just yields to another error:

  Failed to move to new namespace: PID namespaces supported, Network namespace supported, but failed: errno = Operation not permitted
  

/workspaces/photo-location-map/node_modules/electron/dist/electron exited with signal SIGTRAP ERROR: "electron:serve" exited with 1.