Add ${activeEditorLanguageId} variable to window title

[Copilot]

Adds a new ${activeEditorLanguageId} template variable to the window title configuration. This enables reliable language detection for accessibility tools like Talon, which previously had to parse file extensions from the title—a method that breaks for untitled documents.

Implementation

• windowTitle.ts: Retrieves language ID from active text editor's model, handling both code editors and diff editors
• workbench.contribution.ts: Documents the new variable alongside existing window title variables

Usage

{
  "window.title": "${activeEditorShort}${separator}${activeEditorLanguageId}${separator}${rootName}"
}

Produces:

• myFile.ts - typescript - vscode
• Untitled-1 - plaintext - workspace (works without file extensions)
• App.jsx - javascriptreact - my-app (precise language modes)

Returns empty string when no text editor is active.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Variable in window.title for language id of active editor</issue_title>
<issue_description>For accessibility purposes, it would be great if we were able to put the language id of the active editor in the window title.

Like with @meganrogge's #190613, this window title variable would enable us to easily get critical information to Talon in real time to enable appropriate voice commands

Fwiw today we look for the file extension in the window title (eg .ts or .py) to determine language, but that is not completely reliable; eg it breaks for untitled documents

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Variable in window.title for language id of active editor #197663

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[meganrogge]

@bpasero just taking care of low hanging fruit + an easy accessiblity win

[Copilot]

Pull request overview

This PR adds a new ${activeEditorLanguageId} template variable to the window title configuration, enabling accessibility tools like Talon to reliably detect the current language mode without parsing file extensions.

Key Changes:

• Introduces language ID retrieval from the active text editor's model, supporting both regular code editors and diff editors
• Adds documentation for the new variable in the configuration registry

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/vs/workbench/browser/parts/titlebar/windowTitle.ts	Implements language ID extraction from active editor model (lines 364-376) and adds it to the title template variables (line 402)
src/vs/workbench/browser/workbench.contribution.ts	Documents the new ${activeEditorLanguageId} variable in the configuration schema with an example

[bpasero]

@meganrogge much easier by using this:

const activeEditorLanguageId = this.editorService.activeTextEditorLanguageId;