diff --git a/ftdetect/nuwiki.vim b/ftdetect/nuwiki.vim
index b858a8c..5f22638 100644
--- a/ftdetect/nuwiki.vim
+++ b/ftdetect/nuwiki.vim
@@ -3,5 +3,10 @@
 " Users who configure a custom `file_extension` in setup() should add their
 " own `:autocmd BufRead,BufNewFile *.myext setfiletype vimwiki` mapping;
 " we hardcode `.wiki` since ftdetect runs before any user setup() call.
+"
+" Use `set filetype=…` (not `setfiletype`) so we override Neovim's bundled
+" `*.wiki → mediawiki` rule. Users who actually want MediaWiki on .wiki
+" can override this with their own autocmd at a later runtimepath entry,
+" or with `vim.filetype.add` in Neovim.
 
-autocmd! BufRead,BufNewFile *.wiki setfiletype vimwiki
+autocmd! BufRead,BufNewFile *.wiki set filetype=vimwiki
diff --git a/ftplugin/nuwiki.vim b/ftplugin/vimwiki.vim
similarity index 100%
rename from ftplugin/nuwiki.vim
rename to ftplugin/vimwiki.vim
diff --git a/lua/nuwiki/ftplugin.lua b/lua/nuwiki/ftplugin.lua
index 1b1ab9c..805d706 100644
--- a/lua/nuwiki/ftplugin.lua
+++ b/lua/nuwiki/ftplugin.lua
@@ -9,34 +9,33 @@ local function setup_folding(bufnr, folding_mode)
   if folding_mode == 'off' then
     return
   end
-  if folding_mode == 'expr' then
-    vim.api.nvim_set_option_value('foldmethod', 'expr', { buf = bufnr })
-    vim.api.nvim_set_option_value(
-      'foldexpr',
-      'v:lua.require("nuwiki.folding").expr()',
-      { buf = bufnr }
-    )
-    vim.api.nvim_set_option_value(
-      'foldtext',
-      'v:lua.require("nuwiki.folding").foldtext()',
-      { buf = bufnr }
-    )
-    return
-  end
-  -- folding_mode == 'lsp' (default): rely on the server's
-  -- `foldingRange` capability. Neovim 0.11+ enables it automatically
-  -- via `vim.lsp.foldexpr`. Older versions get the regex fallback.
-  if vim.fn.has('nvim-0.11') == 1 and vim.lsp.foldexpr then
-    vim.api.nvim_set_option_value('foldmethod', 'expr', { buf = bufnr })
-    vim.api.nvim_set_option_value(
-      'foldexpr',
-      'v:lua.vim.lsp.foldexpr()',
-      { buf = bufnr }
-    )
-  else
-    -- Pre-0.11 — degrade to the regex fallback so users still get folds.
-    setup_folding(bufnr, 'expr')
+  -- `foldmethod` / `foldexpr` / `foldtext` are window-local options.
+  -- The ftplugin runs during BufRead → FileType, by which time the
+  -- buffer is displayed in the current window. `vim.opt_local` writes
+  -- to the current window's view of the option.
+  local apply = function()
+    if folding_mode == 'expr'
+       or not (vim.fn.has('nvim-0.11') == 1 and vim.lsp.foldexpr)
+    then
+      vim.opt_local.foldmethod = 'expr'
+      vim.opt_local.foldexpr = 'v:lua.require("nuwiki.folding").expr()'
+      vim.opt_local.foldtext = 'v:lua.require("nuwiki.folding").foldtext()'
+    else
+      -- LSP-backed folding via Neovim 0.11+'s built-in foldexpr.
+      vim.opt_local.foldmethod = 'expr'
+      vim.opt_local.foldexpr = 'v:lua.vim.lsp.foldexpr()'
+    end
   end
+
+  -- Set on the current window first (the one that triggered the
+  -- ftplugin). Also re-apply on any future split that views this
+  -- buffer, so `<C-w>v` / `:split` preserves the fold method.
+  apply()
+  vim.api.nvim_create_autocmd('BufWinEnter', {
+    buffer = bufnr,
+    group = vim.api.nvim_create_augroup('nuwiki_folding_' .. bufnr, { clear = true }),
+    callback = apply,
+  })
 end
 
 function M.attach(bufnr)
diff --git a/lua/nuwiki/init.lua b/lua/nuwiki/init.lua
index 556e2b8..d11cc32 100644
--- a/lua/nuwiki/init.lua
+++ b/lua/nuwiki/init.lua
@@ -15,6 +15,20 @@ local lsp = require('nuwiki.lsp')
 
 function M.setup(opts)
   config.apply(opts or {})
+
+  -- Neovim 0.7+ resolves filetypes via `vim.filetype.match` before any
+  -- `ftdetect/*.vim` autocmd fires, and its bundled rule for `*.wiki`
+  -- returns `mediawiki`. Register an authoritative rule here so this
+  -- plugin's filetype (vimwiki) wins.
+  if vim.filetype and vim.filetype.add then
+    local extensions = { wiki = 'vimwiki' }
+    local ext = (config.options.file_extension or '.wiki'):gsub('^%.', '')
+    if ext ~= 'wiki' and ext ~= '' then
+      extensions[ext] = 'vimwiki'
+    end
+    vim.filetype.add({ extension = extensions })
+  end
+
   lsp.register()
 end
 
diff --git a/syntax/nuwiki.vim b/syntax/vimwiki.vim
similarity index 100%
rename from syntax/nuwiki.vim
rename to syntax/vimwiki.vim