Zed: region folding with custom-code-folding

Zed has no built-in support for #region/#endregion-style folding (unlike VS Code). The zed-custom-code-folding extension adds it via an LSP server that implements textDocument/foldingRange, covering 40+ languages including C#. Use this guide to install it and, if you write C#, fix its region syntax so it actually matches.

Prerequisites

• Zed editor.

Steps

1. Install the extension

Open the command palette (Ctrl+Shift+P) → zed: extensions → search “Custom Code Folding” → Install. No build step is needed; it’s published on the Zed extension marketplace.

2. Enable LSP folding ranges

The extension only works once LSP folding ranges are enabled. This replaces Zed’s built-in indent/tree-sitter folding, but structural folds (functions, classes) are preserved because Zed merges ranges from all active language servers. Add to settings.json:

{
  "document_folding_ranges": "on"
}

At this point the extension’s two default patterns work: region (requires a comment prefix — //, /*, or # — before #region/#endregion) and plus-minus (# +++ Section Name … # ---).

3. Add a custom pattern for C#

C#‘s native region syntax is a bare preprocessor directive — #region Name / #endregion with no comment prefix. The default region pattern requires a prefix, so it does not match C# out of the box, even though CSharp is in the extension’s supported language list. Add a custom pattern to settings.json:

{
  "document_folding_ranges": "on",
  "lsp": {
    "custom-code-folding": {
      "initialization_options": {
        "include_defaults": true,
        "patterns": [
          {
            "name": "csharp-region",
            "start": "^\\s*#region\\b\\s*(?P<label>.*?)\\s*$",
            "end": "^\\s*#endregion"
          }
        ]
      }
    }
  }
}

The (?P<label>...) capture group is shown as the label when a region is folded.

Verify

Open a C# file with #region/#endregion blocks and confirm they now fold. Zed’s default folding shortcuts (Windows):

Shortcut	Action
Ctrl+K Ctrl+0	editor::FoldAll — folds everything foldable
Ctrl+K Ctrl+J	editor::UnfoldAll
Ctrl+K Ctrl+L	editor::ToggleFold
Ctrl+K Ctrl+1–9	editor::FoldAtLevel_N — fold by indentation depth

Troubleshooting

• Regions still don’t fold after enabling document_folding_ranges: confirm the language server actually attached to the file (it must be a language the extension supports) and that the custom pattern’s start/end regexes match your exact comment style.
• Want to fold only regions, not every foldable block: not directly possible. The extension only supplies fold ranges to Zed via LSP — it cannot add new editor actions or filter FoldAll by kind, since extensions can’t register custom editor commands. FoldAtLevel_N can approximate “regions only” if your regions consistently sit at one indentation depth, but it will also fold any other block at that depth. Auto-folding regions on file open is not supported either — no such setting exists in Zed.

Related

• zed-custom-code-folding on GitHub

Source captures (private)

• Original Zed custom-folding notes (private)