Describe the bug:
I use the R extension in VS Code and have been using the outline view for years (REdditorSupport). Now, the outline view when I use R in VS Code initially displays symbols (functions, sections) correctly when an R file is opened. However, once I add a new section header (e.g., # Testing ----), or add new code, the outline view disappears and shows "No symbols found in document". In the log, I see "[2025-03-24 10:24:21.630] document definitions found: 0".

This makes it difficult to navigate larger R scripts as the document structure is lost whenever I edit the file.

To Reproduce:

• Open an R script that contains some functions and section headers (# Section name ----)

• Observe that the outline view correctly shows these symbols

• Add a new section header (e.g., type # Testing ----)

• Observe that the outline view now shows "No symbols found in document"

• The only way to temporarily restore the outline is to close and reopen the file

Can you fix this issue by yourself?
No

settings.json:

{
  "files.autoSave": "off",
  "terminal.integrated.inheritEnv": false,
  "explorer.autoReveal": false,
  "git.autofetch": true,
  "r.plot.useHttpgd": false,
  // "r.rterm.mac": "/opt/homebrew/bin/R",
  "r.rterm.mac": "/my/radian/path", // note that this is different than r.rterm.mac
  "r.bracketedPaste": true,
  "r.rterm.option": ["--no-save", "--no-restore"],
  "terminal.integrated.env.osx": {
    "R_HOME": "/opt/homebrew/Cellar/r/4.4.3/lib/R"
  },
  "r.rpath.mac": "/opt/homebrew/bin/R",
  "files.exclude": {
    "**/.gitattributes": true,
    "**/.gitignore": true,
    "**/.vscode": true
  },
  "settingsSync.ignoredExtensions": [],
  "workbench.editor.openSideBySideDirection": "right",
  "git.enableSmartCommit": true,
  "git.confirmSync": false,
  "editor.minimap.showSlider": "always",
  "editor.find.autoFindInSelection": "always",
  "git.postCommitCommand": "sync",
  "git.showPushSuccessNotification": true,
  "outline.collapseItems": "alwaysCollapse",
  "r.alwaysUseActiveTerminal": true,
  "notebook.editorOptionsCustomizations": {},
  "notebook.output.scrolling": "force inline",
  "terminal.integrated.shellIntegration.suggestEnabled": true,
  "github.copilot.editor.enableAutoCompletions": true,
  "terminal.integrated.profiles.osx": {
    "bash": {
      "path": "bash",
      "args": ["-l"],
      "icon": "terminal-bash"
    },
    "zsh": {
      "path": "zsh",
      "args": ["-l"]
    },
    "fish": {
      "path": "fish",
      "args": ["-l"]
    },
    "tmux": {
      "path": "tmux",
      "icon": "terminal-tmux"
    },
    "pwsh": {
      "path": "pwsh",
      "icon": "terminal-powershell"
    }
  },
  "terminal.integrated.defaultProfile.osx": "zsh",
  "interactiveWindow.executeWithShiftEnter": true,
  "jupyter.interactiveWindow.textEditor.executeSelection": true,
  "python.terminal.executeInFileDir": true,
  "python.dataScience.sendSelectionToInteractiveWindow": true,
  "python.dataScience.showCellInputCode": false,
  "python.dataScience.textOutputLimit": 500,
  "python.dataScience.notebookFileRoot": "${workspaceFolder}",
  "macros": {
    "runAndMoveCursor": [
      "python.execSelectionInInteractiveWindow",
      "cursorMove"
    ]
  },
  "workbench.editor.splitInGroupLayout": "vertical",
  "r.session.viewers.viewColumn": {
    "view": "Active",
    "plot": "Active",
    "viewer": "Active"
  },
  "workbench.editorAssociations": {
    "*.csv": "gc-excelviewer-csv-editor"
  },
  "editor.codeActionsOnSave": {
    "source.fixAll": "never"
  },
  "editor.formatOnSave": false,
  "editor.formatOnType": false,
  "r.linting.enabled": false,
  "python.linting.enabled": false,
  "eslint.enable": false,
  "r.lsp.enabled": true,
  "r.lsp.diagnostics": true,
  "r.lsp.debug": true,
  "r.sessionWatcher": true,
  "files.associations": {
    "*.rmd": "markdown"
  },
  "workbench.secondarySideBar.showLabels": false
}

Expected behavior:
The outline view should remain functional and continue to display all symbols even after editing the file or adding new section headers.

Environment:

OS: macOS
VSCode Version: 1.98.2
R Version: 4.4.3
vscode-R version: 2.8.4

Additional context:
I've tried reinstalling the R extension, the languageserver package, and configuring the language server settings, but the issue persists. The outline view works correctly with other file types (e.g., Python) but consistently breaks when editing R files.

I've tried reinstalling the R extension, the languageserver package, and configuring the language server settings, but the issue persists. The outline view works correctly with other file types (e.g., Python) but consistently breaks when editing R files.

Expected behavior:

The outline view should remain functional and continue to display all symbols even after editing the file or adding new section headers.