src/vs/workbench/contrib/comments/browser/commentsEditorContribution.ts/getActiveController
function getActiveController(accessor: ServicesAccessor): CommentController | undefined {
	const activeEditor = getActiveEditor(accessor);
	if (!activeEditor) {
		return undefined;
	}

	const controller = CommentController.get(activeEditor);
	if (!controller) {
		return undefined;
	}
	return controller;
}