diff --git a/README.md b/README.md
index 814ed39..7c5e22f 100644
--- a/README.md
+++ b/README.md
@@ -276,6 +276,8 @@ require'navigator'.setup({
   keymaps = {{key = "gK", func = vim.lsp.declaration, desc = 'declaration'}}, -- a list of key maps
   -- this kepmap gK will override "gD" mapping function declaration()  in default kepmap
   -- please check mapping.lua for all keymaps
+  -- rule of overriding: if func and mode ('n' by default) is same
+  -- it can be overrided
   treesitter_analysis = true, -- treesitter variable context
   treesitter_navigation = true, -- bool|table false: use lsp to navigate between symbol ']r/[r', table: a list of
   --lang using TS navigation
diff --git a/lua/navigator/dochighlight.lua b/lua/navigator/dochighlight.lua
index 4158f25..4e15bdc 100644
--- a/lua/navigator/dochighlight.lua
+++ b/lua/navigator/dochighlight.lua
@@ -223,7 +223,7 @@ local nav_doc_hl = function(bufnr)
   trace('nav_doc_hl', bufnr)
   bufnr = bufnr or vim.api.nvim_get_current_buf()
   local ref_params = vim.lsp.util.make_position_params()
-  vim.lsp.for_each_buffer_client(bufnr, function(client, _, _)
+  util.for_each_buffer_client(bufnr, function(client, _, _)
     if client.server_capabilities.documentHighlightProvider == true then
       trace('sending doc highlight', client.name, bufnr)
       client.request('textDocument/documentHighlight', ref_params, handle_document_highlight, bufnr)
diff --git a/lua/navigator/hover.lua b/lua/navigator/hover.lua
index 83e03c8..6594263 100644
--- a/lua/navigator/hover.lua
+++ b/lua/navigator/hover.lua
@@ -1,59 +1,42 @@
 local lsp = vim.lsp
 local util = lsp.util
 local nutils = require('navigator.util')
+local api = vim.api
 local log = nutils.log
 local M = {}
+
 function M.handler(_, result, ctx, config)
   config = config or {}
   config.focus_id = ctx.method
-  config.zindex = 53
-  if not (result and result.contents) then
-    -- vim.notify('No information available')
-    vim.schedule(function()
-      vim.lsp.buf.signature_help()
-    end)
+  if api.nvim_get_current_buf() ~= ctx.bufnr then
+    -- Ignore result since buffer changed. This happens for slow language servers.
     return
   end
-  local ft = vim.bo.ft
-  -- require('navigator.util').log(result)
-  local markdown_lines = util.convert_input_to_markdown_lines(result.contents)
-  markdown_lines = nutils.trim_empty_lines(markdown_lines)
-  if vim.tbl_isempty(markdown_lines) then
+  if not (result and result.contents) then
+    if config.silent ~= true then
+      vim.notify('No information available')
+    end
     vim.schedule(function()
+      -- fallback to signature help
       vim.lsp.buf.signature_help()
     end)
     return
   end
-
-  local opts = {}
-  opts.wrap = true -- wrapping by default
-  opts.stylize_markdown = true
-  opts.focus = true
-  local contents = markdown_lines
-  if vim.fn.has('nvim-0.10') == 0 then
-    contents = util._trim(markdown_lines, opts) -- function removed in 0.10
+  local format = 'markdown'
+  local contents ---@type string[]
+  if type(result.contents) == 'table' and result.contents.kind == 'plaintext' then
+    format = 'plaintext'
+    contents = vim.split(result.contents.value or '', '\n', { trimempty = true })
   else
-    contents = markdown_lines
+    contents = util.convert_input_to_markdown_lines(result.contents)
   end
-
-  -- applies the syntax and sets the lines to the buffer
-  local bufnr, winnr = util.open_floating_preview(contents, 'markdown', config)
-
-  vim.api.nvim_buf_set_option(bufnr, 'modifiable', true)
-  contents = lsp.util.stylize_markdown(bufnr, contents, opts)
-  vim.api.nvim_buf_set_option(bufnr, 'modifiable', false)
-  if _NgConfigValues.lsp.hover.keymaps then
-    for key, v in pairs(_NgConfigValues.lsp.hover.keymaps) do
-      if v[ft] == nil or v[ft] == true then
-        local f = v.default or function() end
-        vim.keymap.set('n', key, f, { noremap = true, silent = true, buffer = bufnr })
-      else
-        local f = v[ft]
-        vim.keymap.set('n', key, f, { noremap = true, silent = true, buffer = bufnr })
-      end
+  if vim.tbl_isempty(contents) then
+    if config.silent ~= true then
+      vim.notify('No information available')
     end
+    return
   end
-  return bufnr, winnr
+  return util.open_floating_preview(contents, format, config)
 end
 
 return M
diff --git a/lua/navigator/lspclient/mapping.lua b/lua/navigator/lspclient/mapping.lua
index 0d28914..7e98758 100644
--- a/lua/navigator/lspclient/mapping.lua
+++ b/lua/navigator/lspclient/mapping.lua
@@ -12,152 +12,54 @@ if vim.diagnostic == nil then
 end
 local double = { '╔', '═', '╗', '║', '╝', '═', '╚', '║' }
 local single = { '╭', '─', '╮', '│', '╯', '─', '╰', '│' }
--- TODO https://github.com/neovim/neovim/pull/16591 use vimkeymap.set/del
--- LuaFormatter off
+-- stylua: ignore start
 local key_maps = {
   { key = 'gr', func = require('navigator.reference').async_ref, desc = 'async_ref' },
   { key = '<Leader>gr', func = require('navigator.reference').reference, desc = 'reference' }, -- reference deprecated
-  {
-    mode = 'i',
-    key = '<M-k>',
-    func = vim.lsp.buf.signature_help,
-    desc = 'signature_help',
-  },
-  {
-    key = '<c-k>',
-    func = vim.lsp.buf.signature_help,
-    desc = 'signature_help',
-  },
-  {
-    key = 'g0',
-    func = require('navigator.symbols').document_symbols,
-    desc = 'document_symbols',
-  },
-  {
-    key = 'gW',
-    func = require('navigator.workspace').workspace_symbol_live,
-    desc = 'workspace_symbol_live',
-  },
+  { mode = 'i', key = '<M-k>', func = vim.lsp.buf.signature_help, desc = 'signature_help' },
+  { key = '<c-k>', func = vim.lsp.buf.signature_help, desc = 'signature_help' },
+  { key = 'g0', func = require('navigator.symbols').document_symbols, desc = 'document_symbols' },
+  { key = 'gW', func = require('navigator.workspace').workspace_symbol_live, desc = 'workspace_symbol_live' },
   { key = '<c-]>', func = require('navigator.definition').definition, desc = 'definition' },
   { key = 'gd', func = require('navigator.definition').definition, desc = 'definition' },
   { key = 'gD', func = vim.lsp.buf.declaration, desc = 'declaration' },
-
-  {
-    key = 'gt',
-    func = vim.lsp.buf.type_definition,
-    desc = 'type_definition',
-  },
-  {
-    key = 'gp',
-    func = require('navigator.definition').definition_preview,
-    desc = 'definition_preview',
-  },
-  {
-    key = 'gP',
-    func = require('navigator.definition').type_definition_preview,
-    desc = 'type_definition_preview',
-  },
+  { key = 'gt', func = vim.lsp.buf.type_definition, desc = 'type_definition' },
+  { key = 'gp', func = require('navigator.definition').definition_preview, desc = 'definition_preview' },
+  { key = 'gP', func = require('navigator.definition').type_definition_preview, desc = 'type_definition_preview' },
   { key = '<Leader>gt', func = require('navigator.treesitter').buf_ts, desc = 'buf_ts' },
   { key = '<Leader>gT', func = require('navigator.treesitter').bufs_ts, desc = 'bufs_ts' },
   { key = '<Leader>ct', func = require('navigator.ctags').ctags, desc = 'ctags' },
-  {
-    key = '<Space>ca',
-    mode = 'n',
-    func = require('navigator.codeAction').code_action,
-    desc = 'code_action',
-  },
-  {
-    key = '<Space>ca',
-    mode = 'v',
-    func = require('navigator.codeAction').range_code_action,
-    desc = 'range_code_action',
-  },
+  { key = '<Space>ca', mode = 'n', func = require('navigator.codeAction').code_action, desc = 'code_action' },
+  { key = '<Space>ca', mode = 'v', func = require('navigator.codeAction').range_code_action, desc = 'range_code_action' },
   -- { key = '<Leader>re', func = 'rename()' },
   { key = '<Space>rn', func = require('navigator.rename').rename, desc = 'rename' },
   { key = '<Leader>gi', func = vim.lsp.buf.incoming_calls, desc = 'incoming_calls' },
   { key = '<Leader>go', func = vim.lsp.buf.outgoing_calls, desc = 'outgoing_calls' },
   { key = 'gi', func = vim.lsp.buf.implementation, desc = 'implementation' },
   { key = '<Space>D', func = vim.lsp.buf.type_definition, desc = 'type_definition' },
-  {
-    key = 'gL',
-    func = require('navigator.diagnostics').show_diagnostics,
-    desc = 'show_diagnostics',
-  },
-  {
-    key = 'gG',
-    func = require('navigator.diagnostics').show_buf_diagnostics,
-    desc = 'show_buf_diagnostics',
-  },
-  {
-    key = '<Leader>dt',
-    func = require('navigator.diagnostics').toggle_diagnostics,
-    desc = 'toggle_diagnostics',
-  },
-  {
-    key = ']d',
-    func = vim.diagnostic.goto_next,
-    desc = 'next diagnostics',
-  },
-  {
-    key = '[d',
-    func = vim.diagnostic.goto_prev,
-    desc = 'prev diagnostics',
-  },
-  {
-    key = ']O',
-    func = vim.diagnostic.set_loclist,
-    desc = 'diagnostics set loclist',
-  },
+  { key = 'gL', func = require('navigator.diagnostics').show_diagnostics, desc = 'show_diagnostics' },
+  { key = 'gG', func = require('navigator.diagnostics').show_buf_diagnostics, desc = 'show_buf_diagnostics' },
+  { key = '<Leader>dt', func = require('navigator.diagnostics').toggle_diagnostics, desc = 'toggle_diagnostics' },
+  { key = ']d', func = vim.diagnostic.goto_next, desc = 'next diagnostics' },
+  { key = '[d', func = vim.diagnostic.goto_prev, desc = 'prev diagnostics' },
+  { key = ']O', func = vim.diagnostic.set_loclist, desc = 'diagnostics set loclist' },
   { key = ']r', func = require('navigator.treesitter').goto_next_usage, desc = 'goto_next_usage' },
-  {
-    key = '[r',
-    func = require('navigator.treesitter').goto_previous_usage,
-    desc = 'goto_previous_usage',
-  },
-  {
-    key = '<C-LeftMouse>',
-    func = vim.lsp.buf.definition,
-    desc = 'definition',
-  },
-  {
-    key = 'g<LeftMouse>',
-    func = vim.lsp.buf.implementation,
-    desc = 'implementation',
-  },
-  {
-    key = '<Leader>k',
-    func = require('navigator.dochighlight').hi_symbol,
-    desc = 'hi_symbol',
-  },
-  {
-    key = '<Space>wa',
-    func = require('navigator.workspace').add_workspace_folder,
-    desc = 'add_workspace_folder',
-  },
-  {
-    key = '<Space>wr',
-    func = require('navigator.workspace').remove_workspace_folder,
-    desc = 'remove_workspace_folder',
-  },
+  { key = '[r', func = require('navigator.treesitter').goto_previous_usage, desc = 'goto_previous_usage' },
+  { key = '<C-LeftMouse>', func = vim.lsp.buf.definition, desc = 'definition' },
+  { key = 'g<LeftMouse>', func = vim.lsp.buf.implementation, desc = 'implementation' },
+  { key = '<Leader>k', func = require('navigator.dochighlight').hi_symbol, desc = 'hi_symbol' },
+  { key = '<Space>wa', func = require('navigator.workspace').add_workspace_folder, desc = 'add_workspace_folder' },
+  { key = '<Space>wr', func = require('navigator.workspace').remove_workspace_folder, desc = 'remove_workspace_folder' },
   { key = '<Space>ff', func = vim.lsp.buf.format, mode = 'n', desc = 'format' },
   { key = '<Space>ff', func = vim.lsp.buf.range_formatting, mode = 'v', desc = 'range format' },
+  { key = '<Space>gm', func = require('navigator.formatting').range_format, mode = 'n', desc = 'range format operator e.g gmip' },
+  { key = '<Space>wl', func = require('navigator.workspace').list_workspace_folders, desc = 'list_workspace_folders' },
   {
-    key = '<Space>gm',
-    func = require('navigator.formatting').range_format,
-    mode = 'n',
-    desc = 'range format operator e.g gmip',
-  },
-  {
-    key = '<Space>wl',
-    func = require('navigator.workspace').list_workspace_folders,
-    desc = 'list_workspace_folders',
-  },
-  {
-    key = '<Space>la',
-    mode = 'n',
+    key = '<Space>la', mode = 'n',
     func = require('navigator.codelens').run_action,
     desc = 'run code lens action',
-  },
+  }
+  -- stylua: ignore end
 }
 
 if _NgConfigValues.lsp.hover then
@@ -260,13 +162,6 @@ local function set_mapping(lsp_attach_info)
     end
   end
 
-  local function set_keymap(...)
-    vim.api.nvim_buf_set_keymap(bufnr, ...)
-  end
-
-  -- local function buf_set_option(...)
-  --   vim.api.nvim_buf_set_option(bufnr, ...)
-  -- end
   local doc_fmt, range_fmt, ccls = check_cap(lsp_attach_info)
 
   if ccls then
@@ -279,6 +174,7 @@ local function set_mapping(lsp_attach_info)
       local exists = false
       for _, default in pairs(key_maps) do
         if
+          -- override only if func and mode are the same
           v.func == default.func
           and (v.mode or 'n') == (default.mode or 'n')
           and not default.override
@@ -292,6 +188,7 @@ local function set_mapping(lsp_attach_info)
       end
     end
   else
+    -- disable default mapping
     key_maps = _NgConfigValues.keymaps or {}
     log('setting maps to ', key_maps)
   end
@@ -481,8 +378,6 @@ function M.setup(attach_opts)
       require('navigator.diagnostics').diagnostic_handler
   end
 
-  -- TODO: when active signature merge to neovim, remove this setup:
-
   if
     vim.fn.empty(_NgConfigValues.signature_help_cfg) == 0 or _NgConfigValues.lsp_signature_help
   then
diff --git a/lua/navigator/lspwrapper.lua b/lua/navigator/lspwrapper.lua
index f31ebab..af8527a 100644
--- a/lua/navigator/lspwrapper.lua
+++ b/lua/navigator/lspwrapper.lua
@@ -495,7 +495,7 @@ end
 function M.request(method, hdlr) -- e.g  textDocument/reference
   local bufnr = vim.api.nvim_get_current_buf()
   local ref_params = vim.lsp.util.make_position_params()
-  vim.lsp.for_each_buffer_client(bufnr, function(client, _, _)
+  util.for_each_buffer_client(bufnr, function(client, _, _)
     client.request(method, ref_params, hdlr, bufnr)
   end)
 end
diff --git a/lua/navigator/symbols.lua b/lua/navigator/symbols.lua
index b3ef133..f01f464 100644
--- a/lua/navigator/symbols.lua
+++ b/lua/navigator/symbols.lua
@@ -1,7 +1,8 @@
 local gui = require('navigator.gui')
 local M = {}
-local log = require('navigator.util').log
-local trace = require('navigator.util').trace
+local util = require('navigator.util')
+local log = util.log
+local trace = util.trace
 local lsphelper = require('navigator.lspwrapper')
 local symbol_kind = require('navigator.lspclient.lspkind').symbol_kind
 local symbols_to_items = lsphelper.symbols_to_items
@@ -10,7 +11,7 @@ function M.workspace_symbols(query)
   query = query or pcall(vim.fn.input, 'Query: ')
   local bufnr = vim.api.nvim_get_current_buf()
   local params = { query = query }
-  vim.lsp.for_each_buffer_client(bufnr, function(client, _, _bufnr)
+  util.for_each_buffer_client(bufnr, function(client, _, _bufnr)
     if client.server_capabilities.workspaceSymbolProvider then
       client.request('workspace/symbol', params, M.workspace_symbol_handler, _bufnr)
     end
@@ -23,7 +24,7 @@ function M.document_symbols(opts)
     loc = 'top_center',
     prompt = true,
     -- rawdata = true,
-    api = ' ',
+    api = '󰌱 ',
   }
 
   local bufnr = opts.bufnr or vim.api.nvim_get_current_buf()
@@ -31,7 +32,7 @@ function M.document_symbols(opts)
   local params = vim.lsp.util.make_position_params()
   params.context = { includeDeclaration = true }
   params.query = opts.prompt or ''
-  vim.lsp.for_each_buffer_client(bufnr, function(client, _, _bufnr)
+  util.for_each_buffer_client(bufnr, function(client, _, _bufnr)
     if client.name ~= 'null-ls' and client.server_capabilities.documentSymbolProvider then
       client.request('textDocument/documentSymbol', params, M.document_symbol_handler, _bufnr)
     end
diff --git a/lua/navigator/util.lua b/lua/navigator/util.lua
index 25ca2c3..e9921f6 100644
--- a/lua/navigator/util.lua
+++ b/lua/navigator/util.lua
@@ -563,7 +563,6 @@ function M.sub_match(str)
   return str
 end
 
-
 function M.try_trim_markdown_code_blocks(lines)
   local language_id = lines[1]:match('^```(.*)')
   if language_id then
@@ -595,4 +594,16 @@ function M.trim_empty_lines(lines)
   return new_list
 end
 
+function M.for_each_buffer_client(bufnr, fn)
+  local clients
+  if vim.lsp.get_clients then -- nightly nvim 0.10
+    clients = vim.lsp.get_clients({ bufnr = bufnr })
+  else
+    clients = vim.lsp.buf_get_clients()
+  end
+  for _, client in pairs(clients) do
+    fn(client, client.id, bufnr)
+  end
+end
+
 return M