I use VS Code Server as a Home Assistant integration, but I think, as it is based on VS Code Web, there should be no difference. I have just installed it, and right from the beginning, the context menu looks transparent. I can't imagine this would be helpful for someone. Is this a weird setting or extension, like in this thread?:
How to fix VS Code displaying as see-through or transparent?
Or do you think it is a Home Assistant-related bug?
I looked up the GlassIt-VSC extension but it is uninstalled.
As confirmed in the comments, this is caused by the Dark Reader Chrome extension. See [Bug] Context Menu background color becomes transparent when using the Dark Reader chrome extension #4163 (which is a miscategorization to say it's a Monaco / VS Code bug, since it's not VS Code's fault- it's caused by an unsupported browser extension (see this comment)). A new issue ticket has been opened under the dark reader repo at [Broken Website] Monaco context menu background color becomes transparent #11806.
