diff --git a/README.md b/README.md
index a096cc4..9ddfa7f 100644
--- a/README.md
+++ b/README.md
@@ -75,6 +75,10 @@ lua <<EOF
         -- vim.fn["UltiSnips#Anon"](args.body) -- For `ultisnips` users.
       end,
     },
+    window = {
+      -- completion = cmp.config.window.bordered(),
+      -- documentation = cmp.config.window.bordered(),
+    },
     mapping = {
       ['<C-b>'] = cmp.mapping(cmp.mapping.scroll_docs(-4), { 'i', 'c' }),
       ['<C-f>'] = cmp.mapping(cmp.mapping.scroll_docs(4), { 'i', 'c' }),
@@ -131,85 +135,16 @@ lua <<EOF
 EOF
 ```
 
+
+
 ### Where can I find more completion sources?
 
-A list of available sources can be found in the [Wiki](https://github.com/hrsh7th/nvim-cmp/wiki/List-of-sources) or by searching for projects that match the nvim-cmp [GitHub topic](https://github.com/topics/nvim-cmp).
+- See the [Wiki](https://github.com/hrsh7th/nvim-cmp/wiki/List-of-sources)
+- See the [GitHub topic](https://github.com/topics/nvim-cmp).
+
+
 
 ### Where can I find advanced configuration examples?
 
-Please see the corresponding [FAQ](#how-to-show-name-of-item-kind-and-source-like-compe) section or [Wiki pages](https://github.com/hrsh7th/nvim-cmp/wiki).
-
-
-Advanced configuration example
-====================
-
-### Use nvim-cmp as smart omnifunc handler.
-
-nvim-cmp can be used as flexible omnifunc manager.
-
-```lua
-local cmp = require('cmp')
-cmp.setup {
-  completion = {
-    autocomplete = false, -- disable auto-completion.
-  },
-}
-
-_G.vimrc = _G.vimrc or {}
-_G.vimrc.cmp = _G.vimrc.cmp or {}
-_G.vimrc.cmp.lsp = function()
-  cmp.complete({
-    config = {
-      sources = {
-        { name = 'nvim_lsp' }
-      }
-    }
-  })
-end
-_G.vimrc.cmp.snippet = function()
-  cmp.complete({
-    config = {
-      sources = {
-        { name = 'vsnip' }
-      }
-    }
-  })
-end
-
-vim.cmd([[
-  inoremap <C-x><C-o> <Cmd>lua vimrc.cmp.lsp()<CR>
-  inoremap <C-x><C-s> <Cmd>lua vimrc.cmp.snippet()<CR>
-]])
-```
-
-### Full managed completion behavior.
-
-```lua
-local cmp = require('cmp')
-
-cmp.setup {
-  completion = {
-    autocomplete = false, -- disable auto-completion.
-  }
-}
-
-_G.vimrc = _G.vimrc or {}
-_G.vimrc.cmp = _G.vimrc.cmp or {}
-_G.vimrc.cmp.on_text_changed = function()
-  local cursor = vim.api.nvim_win_get_cursor(0)
-  local line = vim.api.nvim_get_current_line()
-  local before = string.sub(line, 1, cursor[2] + 1)
-  if before:match('%s*$') then
-    cmp.complete() -- Trigger completion only if the cursor is placed at the end of line.
-  end
-end
-vim.cmd([[
-  augroup vimrc
-    autocmd
-    autocmd TextChanged,TextChangedI,TextChangedP * call luaeval('vimrc.cmp.on_text_changed()')
-  augroup END
-]])
-```
-
-
+See the [Wiki](https://github.com/hrsh7th/nvim-cmp/wiki)
 
diff --git a/doc/cmp.txt b/doc/cmp.txt
index bdb12d0..da11aa0 100644
--- a/doc/cmp.txt
+++ b/doc/cmp.txt
@@ -14,11 +14,10 @@ Command                                                            |cmp-command|
 Highlight                                                        |cmp-highlight|
 Autocmd                                                            |cmp-autocmd|
 Config                                                              |cmp-config|
+Config Helper                                                |cmp-config-helper|
 Develop                                                            |cmp-develop|
 FAQ                                                                    |cmp-faq|
 
-
-
 ==============================================================================
 Abstract                                                          *cmp-abstract*
 
@@ -29,8 +28,6 @@ This is nvim-cmp's document.
 2. The advanced configuration is noted in wiki.
   - https://github.com/hrsh7th/nvim-cmp/wiki
 
-
-
 ==============================================================================
 Concept                                                            *cmp-concept*
 
@@ -39,8 +36,6 @@ Concept                                                            *cmp-concept*
 - Smart handling of key mapping
 - No flicker
 
-
-
 ==============================================================================
 Usage                                                                *cmp-usage*
 
@@ -48,7 +43,7 @@ The recommendation configurations are the below.
 
 NOTE:
   1. You must setup `snippet.expand` function.
-  2. The `cmp.setup.cmdline` won't work if you are using `native` completion menu. 
+  2. The `cmp.setup.cmdline` won't work if you are using `native` completion menu.
   3. You can disable the `default` options via specifying `cmp.config.disable` value.
 >
   call plug#begin(s:plug_dir)
@@ -92,6 +87,10 @@ NOTE:
           -- vim.fn["UltiSnips#Anon"](args.body) -- For `ultisnips` users.
         end,
       },
+      window = {
+        -- completion = cmp.config.window.bordered(),
+        -- documentation = cmp.config.window.bordered(),
+      },
       mapping = {
         ['<C-d>'] = cmp.mapping(cmp.mapping.scroll_docs(-4), { 'i', 'c' }),
         ['<C-f>'] = cmp.mapping(cmp.mapping.scroll_docs(4), { 'i', 'c' }),
@@ -139,7 +138,6 @@ NOTE:
   EOF
 <
 
-
 ==============================================================================
 Function                                                          *cmp-function*
 
@@ -232,8 +230,6 @@ NOTE: You can call these functions in mapping via `<Cmd>lua require('cmp').compl
   - `complete_done`: emit after current completion is done.
   - `confirm_done`: emit after confirmation is done.
 
-
-
 ==============================================================================
 Mapping                                                            *cmp-mapping*
 
@@ -305,8 +301,6 @@ You can also use built-in mapping helpers.
 The built-in mapping helper is only available as a configuration option.
 If you want to call the nvim-cmp features directly, please use |cmp-function| instead.
 
-
-
 ==============================================================================
 Command                                                            *cmp-command*
 
@@ -315,8 +309,6 @@ Command                                                            *cmp-command*
   Sometimes `unknown` source will be printed but it isn't problem. (e.g. `cmp-nvim-lsp`)
   That the reason is the `cmp-nvim-lsp` will registered on the InsertEnter autocmd.
 
-
-
 ==============================================================================
 Highlight                                                        *cmp-highlight*
 
@@ -345,7 +337,6 @@ Highlight                                                        *cmp-highlight*
   The menu field's highlight group.
 
 
-
 ==============================================================================
 Autocmd                                                            *cmp-autocmd*
 
@@ -418,7 +409,7 @@ formatting.fields~
 formatting.format~
   `fun(entry: cmp.Entry, vim_item: vim.CompletedItem): vim.CompletedItem`
   The function to customize the completion menu appearance. See |complete-items|.
-  This value also can be used to modify `dup` property. 
+  This value also can be used to modify `dup` property.
   NOTE: The `vim.CompletedItem` can have special properties `abbr_hl_group`,
   `kind_hl_group` and `menu_hl_group`.
 
@@ -524,6 +515,32 @@ view~
   Specify the view class to customize appearance.
   Currently, the possible configurations are:
 
+                           *cmp-config.window.{completion,documentation}.border*
+window.{completion,documentation}.border~
+  `string | string[] | nil`
+  Border characters used for the completion popup menu when
+  |experimental.native_menu| is disabled.
+
+                     *cmp-config.window.{completion,documentation}.winhighlight*
+window.{completion,documentation}.winhighlight~
+  `string | cmp.WinhighlightConfig`
+  Specify the window's winhighlight option.
+
+                           *cmp-config.window.{completion,documentation}.zindex*
+window.{completion,documentation}.zindex~
+  `number`
+  The completion window's zindex.
+
+                                     *cmp-config.window.documentation.max_width*
+window.documentation.max_width~
+  `number`
+  The documentation window's max width.
+
+                                    *cmp-config.window.documentation.max_height*
+window.documentation.max_height~
+  `number`
+  The documentation window's max height.
+
                                             *cmp-config.experimental.ghost_text*
 experimental.ghost_text~
   `boolean | { hl_group = string }`
@@ -531,6 +548,66 @@ experimental.ghost_text~
 
 
 
+==============================================================================
+Config Helper                                                *cmp-config-helper*
+
+You can use the following configuration helpers.
+
+cmp.config.compare~
+
+  TBD
+
+cmp.config.context~
+
+  The `cmp.config.context` can be used to context-aware completion toggling. 
+>
+    cmp.setup {
+      enabled = function()
+        -- disable completion if the cursor is `Comment` syntax group. 
+        return not cmp.config.context.in_syntax_group('Comment')
+      end
+    }
+<
+  *cmp.config.context.in_syntax_group* (group)
+    You can specify the vim's built-in syntax group.
+    If you use tree-sitter, You should use `cmp.config.context.in_treesitter_capture` instead. 
+
+  *cmp.config.context.in_treesitter_capture* (capture)
+    You can specify the treesitter capture name.
+    If you don't use `nvim-treesitter`, this helper does not work correctly.
+
+cmp.config.mapping~
+
+  See |:help cmp-mapping|
+
+cmp.config.sources~
+
+  *cmp.config.sources* (...sources)
+    You can specify multiple sources arrays.
+    The sources are grouped in the order you specify, and the groups are displayed in a fallback, like chain completion.
+>
+    cmp.setup {
+      window = {
+        completion = cmp.config.window.bordered(),
+        documentation = cmp.config.window.bordered(),
+      }
+    }
+<
+cmp.config.window~
+
+  *cmp.config.window.bordered* (option)
+    Specify some window as `bordered`.
+    The option is described in the `cmp.ConfigSchema`.
+>
+    cmp.setup {
+      window = {
+        completion = cmp.config.window.bordered(),
+        documentation = cmp.config.window.bordered(),
+      }
+    }
+<
+
+
 ==============================================================================
 Develop                                                            *cmp-develop*
 
@@ -611,7 +688,6 @@ You can create custom source like the following example.
   require('cmp').register_source('month', source.new())
 <
 
-
 ==============================================================================
 FAQ                                                                    *cmp-faq*
 
@@ -628,7 +704,6 @@ How to disable the preselect feature? ~
   }
 <
 
-
 How to disable auto-completion?~
 How to use nvim-cmp as like omnifunc?~
 
@@ -660,6 +735,17 @@ How to setup on the specific buffer?~
   })
 <
 
+How to disable documentation window?~
+
+  You can specify the following config.
+>
+  cmp.setup.filetype({ 'markdown', 'help' }, {
+    window = {
+      documentation = cmp.config.disable
+    }
+  })
+<
+
 How to integrate with copilot.vim?~
 
   The copilot.vim and nvim-cmp both have a `key-mapping fallback` mechanism.
@@ -689,8 +775,5 @@ How to customize menu appearance?~
 
   You can see the nvim-cmp wiki (https://github.com/hrsh7th/nvim-cmp/wiki).
 
-
-
 ==============================================================================
- vim:tw=78:ts=4:et:ft=help:norl:
-
+ vim:tw=78:ts=2:et:ft=help:norl:
diff --git a/lua/cmp/config.lua b/lua/cmp/config.lua
index 1772184..12f3211 100644
--- a/lua/cmp/config.lua
+++ b/lua/cmp/config.lua
@@ -29,7 +29,7 @@ config.onetime = {}
 ---Set configuration for global.
 ---@param c cmp.ConfigSchema
 config.set_global = function(c)
-  config.global = misc.merge(config.normalize(c), config.normalize(config.global))
+  config.global = config.normalize(misc.merge(c, config.global))
   config.global.revision = config.global.revision or 1
   config.global.revision = config.global.revision + 1
 end
@@ -82,7 +82,7 @@ config.get = function()
       global_config.revision or 0,
       onetime_config.revision or 0,
     }, function()
-      return misc.merge(config.normalize(onetime_config), config.normalize(global_config))
+      return config.normalize(misc.merge(onetime_config, global_config))
     end)
   elseif api.is_cmdline_mode() then
     local cmdtype = vim.fn.getcmdtype()
@@ -94,7 +94,7 @@ config.get = function()
       cmdtype,
       cmdline_config.revision or 0,
     }, function()
-      return misc.merge(config.normalize(cmdline_config), config.normalize(global_config))
+      return config.normalize(misc.merge(cmdline_config, global_config))
     end)
   else
     local bufnr = vim.api.nvim_get_current_buf()
@@ -111,9 +111,9 @@ config.get = function()
       buffer_config.revision or 0,
     }, function()
       local c = {}
-      c = misc.merge(c, config.normalize(buffer_config))
-      c = misc.merge(c, config.normalize(filetype_config))
-      c = misc.merge(c, config.normalize(global_config))
+      c = config.normalize(misc.merge(c, buffer_config))
+      c = config.normalize(misc.merge(c, filetype_config))
+      c = config.normalize(misc.merge(c, global_config))
       return c
     end)
   end
@@ -160,6 +160,7 @@ config.normalize = function(c)
   -- make sure c is not 'nil'
   c = c == nil and {} or c
 
+  -- Normalize mapping.
   if c.mapping then
     local normalized = {}
     for k, v in pairs(c.mapping) do
@@ -168,6 +169,7 @@ config.normalize = function(c)
     c.mapping = normalized
   end
 
+  -- Notice experimental.native_menu.
   if c.experimental and c.experimental.native_menu then
     vim.api.nvim_echo({
       { '[nvim-cmp] ', 'Normal' },
@@ -182,6 +184,7 @@ config.normalize = function(c)
     c.view.entries = c.view.entries or 'native'
   end
 
+  -- Notice sources.[n].opts
   if c.sources then
     for _, s in ipairs(c.sources) do
       if s.opts and not s.option then
diff --git a/lua/cmp/config/compare.lua b/lua/cmp/config/compare.lua
index 91db9fc..b198773 100644
--- a/lua/cmp/config/compare.lua
+++ b/lua/cmp/config/compare.lua
@@ -145,7 +145,7 @@ compare.locality = setmetatable({
         self.locality_map[w] = math.min(self.locality_map[w] or d, math.abs(i - cursor_row))
       end
     end
-  end
+  end,
 }, {
   __call = function(self, entry1, entry2)
     local local1 = self.locality_map[entry1:get_word()]
@@ -159,7 +159,7 @@ compare.locality = setmetatable({
       end
       return local1 < local2
     end
-  end
+  end,
 })
 
 -- scopes
diff --git a/lua/cmp/config/default.lua b/lua/cmp/config/default.lua
index d596444..d05675f 100644
--- a/lua/cmp/config/default.lua
+++ b/lua/cmp/config/default.lua
@@ -86,12 +86,12 @@ return function()
     },
 
     completion = {
-      keyword_length = 1,
-      keyword_pattern = [[\%(-\?\d\+\%(\.\d\+\)\?\|\h\w*\%(-\w*\)*\)]],
       autocomplete = {
         types.cmp.TriggerEvent.TextChanged,
       },
       completeopt = 'menu,menuone,noselect',
+      keyword_pattern = [[\%(-\?\d\+\%(\.\d\+\)\?\|\h\w*\%(-\w*\)*\)]],
+      keyword_length = 1,
     },
 
     formatting = {
@@ -125,13 +125,6 @@ return function()
 
     sources = {},
 
-    documentation = {
-      border = { '', '', '', ' ', '', '', '', ' ' },
-      winhighlight = 'NormalFloat:NormalFloat,FloatBorder:NormalFloat',
-      maxwidth = math.floor((WIDE_HEIGHT * 2) * (vim.o.columns / (WIDE_HEIGHT * 2 * 16 / 9))),
-      maxheight = math.floor(WIDE_HEIGHT * (WIDE_HEIGHT / vim.o.lines)),
-    },
-
     confirmation = {
       default_behavior = types.cmp.ConfirmBehavior.Insert,
       get_commit_characters = function(commit_characters)
@@ -148,5 +141,18 @@ return function()
     view = {
       entries = { name = 'custom', selection_order = 'top_down' },
     },
+
+    window = {
+      completion = {
+        border = { '', '', '', '', '', '', '', '' },
+        winhighlight = 'Normal:Pmenu,FloatBorder:Pmenu,CursorLine:PmenuSel,Search:None',
+      },
+      documentation = {
+        max_height = math.floor(WIDE_HEIGHT * (WIDE_HEIGHT / vim.o.lines)),
+        max_width = math.floor((WIDE_HEIGHT * 2) * (vim.o.columns / (WIDE_HEIGHT * 2 * 16 / 9))),
+        border = { '', '', '', ' ', '', '', '', ' ' },
+        winhighlight = 'FloatBorder:NormalFloat',
+      },
+    },
   }
 end
diff --git a/lua/cmp/config/window.lua b/lua/cmp/config/window.lua
new file mode 100644
index 0000000..b6fec0f
--- /dev/null
+++ b/lua/cmp/config/window.lua
@@ -0,0 +1,12 @@
+local window = {}
+
+window.bordered = function(opts)
+  opts = opts or {}
+  return {
+    border = opts.border or 'rounded',
+    winhighlight = opts.winhighlight or 'Normal:Normal,FloatBorder:Normal,CursorLine:Visual,Search:None',
+    zindex = opts.zindex or 1001,
+  }
+end
+
+return window
diff --git a/lua/cmp/init.lua b/lua/cmp/init.lua
index dbcd866..ac839cb 100644
--- a/lua/cmp/init.lua
+++ b/lua/cmp/init.lua
@@ -29,6 +29,7 @@ cmp.config.disable = misc.none
 cmp.config.compare = require('cmp.config.compare')
 cmp.config.sources = require('cmp.config.sources')
 cmp.config.mapping = require('cmp.config.mapping')
+cmp.config.window = require('cmp.config.window')
 
 ---Sync asynchronous process.
 cmp.sync = function(callback)
diff --git a/lua/cmp/types/cmp.lua b/lua/cmp/types/cmp.lua
index b4e9402..574e533 100644
--- a/lua/cmp/types/cmp.lua
+++ b/lua/cmp/types/cmp.lua
@@ -75,7 +75,7 @@ cmp.ItemField.Menu = 'menu'
 ---@field public enabled fun():boolean|boolean
 ---@field public preselect cmp.PreselectMode
 ---@field public completion cmp.CompletionConfig
----@field public documentation cmp.DocumentationConfig|"false"
+---@field public window cmp.WindowConfig|nil
 ---@field public confirmation cmp.ConfirmationConfig
 ---@field public matching cmp.MatchingConfig
 ---@field public sorting cmp.SortingConfig
@@ -86,19 +86,23 @@ cmp.ItemField.Menu = 'menu'
 ---@field public view cmp.ViewConfig
 ---@field public experimental cmp.ExperimentalConfig
 
+--- @class cmp.WindowConfig
+--- @field completion cmp.WindowConfig
+--- @field documentation cmp.WindowConfig|nil
+
 ---@class cmp.CompletionConfig
 ---@field public autocomplete cmp.TriggerEvent[]
 ---@field public completeopt string
----@field public keyword_pattern string
----@field public keyword_length number
 ---@field public get_trigger_characters fun(trigger_characters: string[]): string[]
+---@field public keyword_length number
+---@field public keyword_pattern string
 
----@class cmp.DocumentationConfig
----@field public border string[]
+---@class cmp.WindowConfig
+---@field public border string|string[]
 ---@field public winhighlight string
----@field public maxwidth number|nil
----@field public maxheight number|nil
 ---@field public zindex number|nil
+---@field public max_width number|nil
+---@field public max_height number|nil
 
 ---@class cmp.ConfirmationConfig
 ---@field public default_behavior cmp.ConfirmBehavior
diff --git a/lua/cmp/utils/misc.lua b/lua/cmp/utils/misc.lua
index 8dd3529..9535f28 100644
--- a/lua/cmp/utils/misc.lua
+++ b/lua/cmp/utils/misc.lua
@@ -29,6 +29,24 @@ misc.concat = function(list1, list2)
   return new_list
 end
 
+---Repeat values
+---@generic T
+---@param str_or_tbl T
+---@param count number
+---@return T
+misc.rep = function(str_or_tbl, count)
+  if type(str_or_tbl) == 'string' then
+    return string.rep(str_or_tbl, count)
+  end
+  local rep = {}
+  for _ = 1, count do
+    for _, v in ipairs(str_or_tbl) do
+      table.insert(rep, v)
+    end
+  end
+  return rep
+end
+
 ---Return the valu is empty or not.
 ---@param v any
 ---@return boolean
diff --git a/lua/cmp/utils/str.lua b/lua/cmp/utils/str.lua
index 450c991..bca210c 100644
--- a/lua/cmp/utils/str.lua
+++ b/lua/cmp/utils/str.lua
@@ -1,5 +1,4 @@
 local char = require('cmp.utils.char')
-local pattern = require('cmp.utils.pattern')
 
 local str = {}
 
@@ -73,23 +72,6 @@ str.remove_suffix = function(text, suffix)
   return string.sub(text, 1, -#suffix - 1)
 end
 
----strikethrough
----@param text string
----@return string
-str.strikethrough = function(text)
-  local r = pattern.regex('.')
-  local buffer = ''
-  while text ~= '' do
-    local s, e = r:match_str(text)
-    if not s then
-      break
-    end
-    buffer = buffer .. string.sub(text, s, e) .. '̶'
-    text = string.sub(text, e + 1)
-  end
-  return buffer
-end
-
 ---trim
 ---@param text string
 ---@return string
diff --git a/lua/cmp/utils/str_spec.lua b/lua/cmp/utils/str_spec.lua
index 541414f..1a21855 100644
--- a/lua/cmp/utils/str_spec.lua
+++ b/lua/cmp/utils/str_spec.lua
@@ -12,10 +12,6 @@ describe('utils.str', function()
     assert.are.equal(str.get_word('import { GetStaticProps$1 } from "next";', nil, 9), 'import { GetStaticProps')
   end)
 
-  it('strikethrough', function()
-    assert.are.equal(str.strikethrough('あいうえお'), 'あ̶い̶う̶え̶お̶')
-  end)
-
   it('remove_suffix', function()
     assert.are.equal(str.remove_suffix('log()', '$0'), 'log()')
     assert.are.equal(str.remove_suffix('log()$0', '$0'), 'log()')
diff --git a/lua/cmp/utils/window.lua b/lua/cmp/utils/window.lua
index 8e2bf02..a8a271e 100644
--- a/lua/cmp/utils/window.lua
+++ b/lua/cmp/utils/window.lua
@@ -9,13 +9,14 @@ local api = require('cmp.utils.api')
 ---@field public col number
 ---@field public width number
 ---@field public height number
+---@field public border string|string[]|nil
 ---@field public zindex number|nil
 
 ---@class cmp.Window
 ---@field public name string
 ---@field public win number|nil
----@field public swin1 number|nil
----@field public swin2 number|nil
+---@field public thumb_win number|nil
+---@field public sbar_win number|nil
 ---@field public style cmp.WindowStyle
 ---@field public opt table<string, any>
 ---@field public buffer_opt table<string, any>
@@ -28,8 +29,8 @@ window.new = function()
   local self = setmetatable({}, { __index = window })
   self.name = misc.id('cmp.utils.window.new')
   self.win = nil
-  self.swin1 = nil
-  self.swin2 = nil
+  self.sbar_win = nil
+  self.thumb_win = nil
   self.style = {}
   self.cache = cache.new()
   self.opt = {}
@@ -79,13 +80,13 @@ end
 ---Set style.
 ---@param style cmp.WindowStyle
 window.set_style = function(self, style)
-  if vim.o.columns and vim.o.columns <= style.col + style.width then
-    style.width = vim.o.columns - style.col - 1
-  end
-  if vim.o.lines and vim.o.lines <= style.row + style.height then
-    style.height = vim.o.lines - style.row - 1
-  end
   self.style = style
+  local info = self:info()
+
+  if vim.o.lines and vim.o.lines <= info.row + info.height + 1 then
+    self.style.height = vim.o.lines - info.row - info.border_info.vert - 1
+  end
+
   self.style.zindex = self.style.zindex or 1
 end
 
@@ -127,49 +128,57 @@ end
 
 ---Update
 window.update = function(self)
-  if self:has_scrollbar() then
-    local total = self:get_content_height()
-    local info = self:info()
-    local bar_height = math.ceil(info.height * (info.height / total))
-    local bar_offset = math.min(info.height - bar_height, math.floor(info.height * (vim.fn.getwininfo(self.win)[1].topline / total)))
-    local style1 = {}
-    style1.relative = 'editor'
-    style1.style = 'minimal'
-    style1.width = 1
-    style1.height = info.height
-    style1.row = info.row
-    style1.col = info.col + info.width - (info.has_scrollbar and 1 or 0)
-    style1.zindex = (self.style.zindex and (self.style.zindex + 1) or 1)
-    if self.swin1 and vim.api.nvim_win_is_valid(self.swin1) then
-      vim.api.nvim_win_set_config(self.swin1, style1)
-    else
-      style1.noautocmd = true
-      self.swin1 = vim.api.nvim_open_win(buffer.ensure(self.name .. 'sbuf1'), false, style1)
-      vim.api.nvim_win_set_option(self.swin1, 'winhighlight', 'EndOfBuffer:PmenuSbar,Normal:PmenuSbar,NormalNC:PmenuSbar,NormalFloat:PmenuSbar')
+  local info = self:info()
+  if info.scrollable then
+    -- Draw the background of the scrollbar
+
+    if not info.border_info.visible then
+      local style = {
+        relative = 'editor',
+        style = 'minimal',
+        width = 1,
+        height = self.style.height,
+        row = info.row,
+        col = info.col + info.width - info.scrollbar_offset, -- info.col was already contained the scrollbar offset.
+        zindex = (self.style.zindex and (self.style.zindex + 1) or 1),
+      }
+      if self.sbar_win and vim.api.nvim_win_is_valid(self.sbar_win) then
+        vim.api.nvim_win_set_config(self.sbar_win, style)
+      else
+        style.noautocmd = true
+        self.sbar_win = vim.api.nvim_open_win(buffer.ensure(self.name .. 'sbar_buf'), false, style)
+        vim.api.nvim_win_set_option(self.sbar_win, 'winhighlight', 'EndOfBuffer:PmenuSbar,NormalFloat:PmenuSbar')
+      end
     end
-    local style2 = {}
-    style2.relative = 'editor'
-    style2.style = 'minimal'
-    style2.width = 1
-    style2.height = bar_height
-    style2.row = info.row + bar_offset
-    style2.col = info.col + info.width - (info.has_scrollbar and 1 or 0)
-    style2.zindex = (self.style.zindex and (self.style.zindex + 2) or 2)
-    if self.swin2 and vim.api.nvim_win_is_valid(self.swin2) then
-      vim.api.nvim_win_set_config(self.swin2, style2)
+
+    -- Draw the scrollbar thumb
+    local thumb_height = math.floor(info.inner_height * (info.inner_height / self:get_content_height()) + 0.5)
+    local thumb_offset = math.floor(info.inner_height * (vim.fn.getwininfo(self.win)[1].topline / self:get_content_height()))
+
+    local style = {
+      relative = 'editor',
+      style = 'minimal',
+      width = 1,
+      height = math.max(1, thumb_height),
+      row = info.row + thumb_offset + (info.border_info.visible and info.border_info.top or 0),
+      col = info.col + info.width - 1, -- info.col was already added scrollbar offset.
+      zindex = (self.style.zindex and (self.style.zindex + 2) or 2),
+    }
+    if self.thumb_win and vim.api.nvim_win_is_valid(self.thumb_win) then
+      vim.api.nvim_win_set_config(self.thumb_win, style)
     else
-      style2.noautocmd = true
-      self.swin2 = vim.api.nvim_open_win(buffer.ensure(self.name .. 'sbuf2'), false, style2)
-      vim.api.nvim_win_set_option(self.swin2, 'winhighlight', 'EndOfBuffer:PmenuThumb,Normal:PmenuThumb,NormalNC:PmenuThumb,NormalFloat:PmenuThumb')
+      style.noautocmd = true
+      self.thumb_win = vim.api.nvim_open_win(buffer.ensure(self.name .. 'thumb_buf'), false, style)
+      vim.api.nvim_win_set_option(self.thumb_win, 'winhighlight', 'EndOfBuffer:PmenuThumb,NormalFloat:PmenuThumb')
     end
   else
-    if self.swin1 and vim.api.nvim_win_is_valid(self.swin1) then
-      vim.api.nvim_win_hide(self.swin1)
-      self.swin1 = nil
+    if self.sbar_win and vim.api.nvim_win_is_valid(self.sbar_win) then
+      vim.api.nvim_win_hide(self.sbar_win)
+      self.sbar_win = nil
     end
-    if self.swin2 and vim.api.nvim_win_is_valid(self.swin2) then
-      vim.api.nvim_win_hide(self.swin2)
-      self.swin2 = nil
+    if self.thumb_win and vim.api.nvim_win_is_valid(self.thumb_win) then
+      vim.api.nvim_win_hide(self.thumb_win)
+      self.thumb_win = nil
     end
   end
 
@@ -188,13 +197,13 @@ window.close = function(self)
       vim.api.nvim_win_hide(self.win)
       self.win = nil
     end
-    if self.swin1 and vim.api.nvim_win_is_valid(self.swin1) then
-      vim.api.nvim_win_hide(self.swin1)
-      self.swin1 = nil
+    if self.sbar_win and vim.api.nvim_win_is_valid(self.sbar_win) then
+      vim.api.nvim_win_hide(self.sbar_win)
+      self.sbar_win = nil
     end
-    if self.swin2 and vim.api.nvim_win_is_valid(self.swin2) then
-      vim.api.nvim_win_hide(self.swin2)
-      self.swin2 = nil
+    if self.thumb_win and vim.api.nvim_win_is_valid(self.thumb_win) then
+      vim.api.nvim_win_hide(self.thumb_win)
+      self.thumb_win = nil
     end
   end
 end
@@ -204,91 +213,101 @@ window.visible = function(self)
   return self.win and vim.api.nvim_win_is_valid(self.win)
 end
 
----Return the scrollbar will shown or not.
-window.has_scrollbar = function(self)
-  return (self.style.height or 0) < self:get_content_height()
-end
-
 ---Return win info.
 window.info = function(self)
-  local border_width = self:get_border_width()
-  local has_scrollbar = self:has_scrollbar()
-  return {
+  local border_info = self:get_border_info()
+  local info = {
     row = self.style.row,
     col = self.style.col,
-    width = self.style.width + border_width + (has_scrollbar and 1 or 0),
-    height = self.style.height,
-    border_width = border_width,
-    has_scrollbar = has_scrollbar,
+    width = self.style.width + border_info.left + border_info.right,
+    height = self.style.height + border_info.top + border_info.bottom,
+    inner_width = self.style.width,
+    inner_height = self.style.height,
+    border_info = border_info,
+    scrollable = false,
+    scrollbar_offset = 0,
   }
+
+  if self:get_content_height() > info.inner_height then
+    info.scrollable = true
+    if not border_info.visible then
+      info.scrollbar_offset = 1
+      info.width = info.width + 1
+    end
+  end
+
+  return info
 end
 
----Get border width
----@return number
-window.get_border_width = function(self)
+---Return border information.
+---@return { top: number, left: number, right: number, bottom: number, vert: number, horiz: number, visible: boolean }
+window.get_border_info = function(self)
   local border = self.style.border
-  if type(border) == 'table' then
-    local new_border = {}
-    while #new_border < 8 do
-      for _, b in ipairs(border) do
-        table.insert(new_border, b)
-      end
+  if not border or border == 'none' then
+    return {
+      top = 0,
+      left = 0,
+      right = 0,
+      bottom = 0,
+      vert = 0,
+      horiz = 0,
+      visible = false,
+    }
+  end
+  if type(border) == 'string' then
+    if border == 'shadow' then
+      return {
+        top = 0,
+        left = 0,
+        right = 1,
+        bottom = 1,
+        vert = 1,
+        horiz = 1,
+        visible = false,
+      }
     end
-    border = new_border
+    return {
+      top = 1,
+      left = 1,
+      right = 1,
+      bottom = 1,
+      vert = 2,
+      horiz = 2,
+      visible = true,
+    }
   end
 
-  local w = 0
-  if border then
-    if type(border) == 'string' then
-      if border == 'single' then
-        w = 2
-      elseif border == 'solid' then
-        w = 2
-      elseif border == 'double' then
-        w = 2
-      elseif border == 'rounded' then
-        w = 2
-      elseif border == 'shadow' then
-        w = 1
-      end
-    elseif type(border) == 'table' then
-      local b4 = type(border[4]) == 'table' and border[4][1] or border[4]
-      if #b4 > 0 then
-        w = w + 1
-      end
-      local b8 = type(border[8]) == 'table' and border[8][1] or border[8]
-      if #b8 > 0 then
-        w = w + 1
-      end
+  local new_border = {}
+  while #new_border <= 8 do
+    for _, b in ipairs(border) do
+      table.insert(new_border, type(b) == 'string' and b or b[1])
     end
   end
-  return w
+  local info = {}
+  info.top = new_border[2] == '' and 0 or 1
+  info.right = new_border[4] == '' and 0 or 1
+  info.bottom = new_border[6] == '' and 0 or 1
+  info.left = new_border[8] == '' and 0 or 1
+  info.vert = info.top + info.bottom
+  info.horiz = info.left + info.right
+  info.visible = not (vim.tbl_contains({ '', ' ' }, new_border[2]) and vim.tbl_contains({ '', ' ' }, new_border[4]) and vim.tbl_contains({ '', ' ' }, new_border[6]) and vim.tbl_contains({ '', ' ' }, new_border[8]))
+  return info
 end
 
 ---Get scroll height.
+---NOTE: The result of vim.fn.strdisplaywidth depends on the buffer it was called in (see comment in cmp.Entry.get_view).
 ---@return number
 window.get_content_height = function(self)
   if not self:option('wrap') then
     return vim.api.nvim_buf_line_count(self:get_buffer())
   end
-
-  return self.cache:ensure({
-    'get_content_height',
-    self.style.width,
-    self:get_buffer(),
-    vim.api.nvim_buf_get_changedtick(self:get_buffer()),
-  }, function()
-    local height = 0
-    local buf = self:get_buffer()
-    -- The result of vim.fn.strdisplaywidth depends on the buffer it was called
-    -- in (see comment in cmp.Entry.get_view).
-    vim.api.nvim_buf_call(buf, function()
-      for _, text in ipairs(vim.api.nvim_buf_get_lines(buf, 0, -1, false)) do
-        height = height + math.ceil(math.max(1, vim.fn.strdisplaywidth(text)) / self.style.width)
-      end
-    end)
-    return height
+  local height = 0
+  vim.api.nvim_buf_call(self:get_buffer(), function()
+    for _, text in ipairs(vim.api.nvim_buf_get_lines(self:get_buffer(), 0, -1, false)) do
+      height = height + math.max(1, math.ceil(vim.fn.strdisplaywidth(text) / self.style.width))
+    end
   end)
+  return height
 end
 
 return window
diff --git a/lua/cmp/view/custom_entries_view.lua b/lua/cmp/view/custom_entries_view.lua
index 0004480..8020a9b 100644
--- a/lua/cmp/view/custom_entries_view.lua
+++ b/lua/cmp/view/custom_entries_view.lua
@@ -25,6 +25,7 @@ custom_entries_view.ns = vim.api.nvim_create_namespace('cmp.view.custom_entries_
 
 custom_entries_view.new = function()
   local self = setmetatable({}, { __index = custom_entries_view })
+
   self.entries_win = window.new()
   self.entries_win:option('conceallevel', 2)
   self.entries_win:option('concealcursor', 'n')
@@ -32,7 +33,6 @@ custom_entries_view.new = function()
   self.entries_win:option('foldenable', false)
   self.entries_win:option('wrap', false)
   self.entries_win:option('scrolloff', 0)
-  self.entries_win:option('winhighlight', 'Normal:Pmenu,FloatBorder:Pmenu,CursorLine:PmenuSel,Search:None')
   -- This is done so that strdisplaywidth calculations for lines in the
   -- custom_entries_view window exactly match with what is really displayed,
   -- see comment in cmp.Entry.get_view. Setting tabstop to 1 makes all tabs be
@@ -118,13 +118,11 @@ custom_entries_view.is_direction_top_down = function(self)
 end
 
 custom_entries_view.open = function(self, offset, entries)
+  local completion = config.get().window.completion
   self.offset = offset
   self.entries = {}
   self.column_width = { abbr = 0, kind = 0, menu = 0 }
 
-  -- Apply window options (that might be changed) on the custom completion menu.
-  self.entries_win:option('winblend', vim.o.pumblend)
-
   local entries_buf = self.entries_win:get_buffer()
   local lines = {}
   local dedup = {}
@@ -159,16 +157,24 @@ custom_entries_view.open = function(self, offset, entries)
   local pos = api.get_screen_cursor()
   local cursor = api.get_cursor()
   local delta = cursor[2] + 1 - self.offset
-  local has_bottom_space = (vim.o.lines - pos[1]) >= DEFAULT_HEIGHT
   local row, col = pos[1], pos[2] - delta - 1
 
-  if not has_bottom_space and math.floor(vim.o.lines * 0.5) <= row and vim.o.lines - row <= height then
+  local border_info = window.get_border_info({ style = completion })
+  local border_offset_row = border_info.top + border_info.bottom
+  local border_offset_col = border_info.left + border_info.right
+  if math.floor(vim.o.lines * 0.5) <= row + border_offset_row and vim.o.lines - row - border_offset_row <= math.min(DEFAULT_HEIGHT, height) then
     height = math.min(height, row - 1)
-    row = row - height - 1
+    row = row - height - border_offset_row - 1
+    if row < 0 then
+      height = height + row
+    end
   end
-  if math.floor(vim.o.columns * 0.5) <= col and vim.o.columns - col <= width then
+  if math.floor(vim.o.columns * 0.5) <= col + border_offset_col and vim.o.columns - col - border_offset_col <= width then
     width = math.min(width, vim.o.columns - 1)
-    col = vim.o.columns - width - 1
+    col = vim.o.columns - width - border_offset_col - 1
+    if col < 0 then
+      width = width + col
+    end
   end
 
   if pos[1] > row then
@@ -187,6 +193,9 @@ custom_entries_view.open = function(self, offset, entries)
     end
   end
 
+  -- Apply window options (that might be changed) on the custom completion menu.
+  self.entries_win:option('winblend', vim.o.pumblend)
+  self.entries_win:option('winhighlight', completion.winhighlight)
   self.entries_win:open({
     relative = 'editor',
     style = 'minimal',
@@ -194,7 +203,8 @@ custom_entries_view.open = function(self, offset, entries)
     col = math.max(0, col),
     width = width,
     height = height,
-    zindex = 1001,
+    border = completion.border,
+    zindex = completion.zindex or 1001,
   })
   -- always set cursor when starting. It will be adjusted on the call to _select
   vim.api.nvim_win_set_cursor(self.entries_win.win, { 1, 0 })
diff --git a/lua/cmp/view/docs_view.lua b/lua/cmp/view/docs_view.lua
index 5a9acb4..9d2cd3f 100644
--- a/lua/cmp/view/docs_view.lua
+++ b/lua/cmp/view/docs_view.lua
@@ -23,7 +23,7 @@ end
 ---@param e cmp.Entry
 ---@param view cmp.WindowStyle
 docs_view.open = function(self, e, view)
-  local documentation = config.get().documentation
+  local documentation = config.get().window.documentation
   if not documentation then
     return
   end
@@ -32,11 +32,12 @@ docs_view.open = function(self, e, view)
     return self:close()
   end
 
-  local right_space = vim.o.columns - (view.col + view.width) - 2
-  local left_space = view.col - 2
-  local maxwidth = math.min(documentation.maxwidth, math.max(left_space, right_space) - 1)
+  local border_info = window.get_border_info({ style = documentation })
+  local right_space = vim.o.columns - (view.col + view.width) - 1
+  local left_space = view.col - 1
+  local max_width = math.min(documentation.max_width, math.max(left_space, right_space))
 
-  -- update buffer content if needed.
+  -- Update buffer content if needed.
   if not self.entry or e.id ~= self.entry.id then
     local documents = e:get_documentation()
     if #documents == 0 then
@@ -46,24 +47,26 @@ docs_view.open = function(self, e, view)
     self.entry = e
     vim.api.nvim_buf_call(self.window:get_buffer(), function()
       vim.cmd([[syntax clear]])
+      vim.api.nvim_buf_set_lines(self.window:get_buffer(), 0, -1, false, {})
     end)
     vim.lsp.util.stylize_markdown(self.window:get_buffer(), documents, {
-      max_width = maxwidth,
-      max_height = documentation.maxheight,
+      max_width = max_width,
+      max_height = documentation.max_height,
     })
   end
 
+  -- Calculate window size.
   local width, height = vim.lsp.util._make_floating_popup_size(vim.api.nvim_buf_get_lines(self.window:get_buffer(), 0, -1, false), {
-    max_width = maxwidth,
-    max_height = documentation.maxheight,
+    max_width = max_width - border_info.horiz,
+    max_height = documentation.max_height - border_info.vert,
   })
   if width <= 0 or height <= 0 then
     return self:close()
   end
 
+  -- Calculate window position.
   local right_col = view.col + view.width
-  local left_col = view.col - width - 2
-
+  local left_col = view.col - width - border_info.horiz
   local col, left
   if right_space >= width and left_space >= width then
     if right_space < left_space then
@@ -81,8 +84,10 @@ docs_view.open = function(self, e, view)
     return self:close()
   end
 
+  -- Render window.
+  self.window:option('winblend', vim.o.pumblend)
   self.window:option('winhighlight', documentation.winhighlight)
-  self.window:set_style({
+  local style = {
     relative = 'editor',
     style = 'minimal',
     width = width,
@@ -91,11 +96,14 @@ docs_view.open = function(self, e, view)
     col = col,
     border = documentation.border,
     zindex = documentation.zindex or 50,
-  })
-  if left and self.window:has_scrollbar() then
-    self.window.style.col = self.window.style.col - 1
+  }
+  self.window:open(style)
+
+  -- Correct left-col for scrollbar existence.
+  if left then
+    style.col = style.col - self.window:info().scrollbar_offset
+    self.window:open(style)
   end
-  self.window:open()
 end
 
 ---Close floating window
diff --git a/lua/cmp/view/native_entries_view.lua b/lua/cmp/view/native_entries_view.lua
index d1dc8de..d8b0b1b 100644
--- a/lua/cmp/view/native_entries_view.lua
+++ b/lua/cmp/view/native_entries_view.lua
@@ -101,7 +101,7 @@ native_entries_view.info = function(self)
   if self:visible() then
     local info = vim.fn.pum_getpos()
     return {
-      width = info.width + (info.scrollbar and 1 or 0),
+      width = info.width + (info.scrollable and 1 or 0),
       height = info.height,
       row = info.row,
       col = info.col,
diff --git a/plugin/cmp.lua b/plugin/cmp.lua
index a977a78..6c0809f 100644
--- a/plugin/cmp.lua
+++ b/plugin/cmp.lua
@@ -80,37 +80,27 @@ misc.set(_G, { 'cmp', 'plugin', 'colorscheme' }, function()
     guibg = 'NONE',
     ctermbg = 'NONE',
   })
+  highlight.inherit('CmpItemMenuDefault', 'Pmenu', {
+    guibg = 'NONE',
+    ctermbg = 'NONE',
+  })
   for name in pairs(types.lsp.CompletionItemKind) do
     if type(name) == 'string' then
       vim.cmd(([[highlight default link CmpItemKind%sDefault CmpItemKind]]):format(name))
     end
   end
-  highlight.inherit('CmpItemMenuDefault', 'Pmenu', {
-    guibg = 'NONE',
-    ctermbg = 'NONE',
-  })
 end)
 _G.cmp.plugin.colorscheme()
 
-if vim.fn.hlexists('CmpItemAbbr') ~= 1 then
-  vim.cmd [[highlight default link CmpItemAbbr CmpItemAbbrDefault]]
-end
+vim.cmd [[
+  highlight default link CmpItemAbbr CmpItemAbbrDefault
+  highlight default link CmpItemAbbrDeprecated CmpItemAbbrDeprecatedDefault
+  highlight default link CmpItemAbbrMatch CmpItemAbbrMatchDefault
+  highlight default link CmpItemAbbrMatchFuzzy CmpItemAbbrMatchFuzzyDefault
+  highlight default link CmpItemKind CmpItemKindDefault
+  highlight default link CmpItemMenu CmpItemMenuDefault
+]]
 
-if vim.fn.hlexists('CmpItemAbbrDeprecated') ~= 1 then
-  vim.cmd [[highlight default link CmpItemAbbrDeprecated CmpItemAbbrDeprecatedDefault]]
-end
-
-if vim.fn.hlexists('CmpItemAbbrMatch') ~= 1 then
-  vim.cmd [[highlight default link CmpItemAbbrMatch CmpItemAbbrMatchDefault]]
-end
-
-if vim.fn.hlexists('CmpItemAbbrMatchFuzzy') ~= 1 then
-  vim.cmd [[highlight default link CmpItemAbbrMatchFuzzy CmpItemAbbrMatchFuzzyDefault]]
-end
-
-if vim.fn.hlexists('CmpItemKind') ~= 1 then
-  vim.cmd [[highlight default link CmpItemKind CmpItemKindDefault]]
-end
 for name in pairs(types.lsp.CompletionItemKind) do
   if type(name) == 'string' then
     local hi = ('CmpItemKind%s'):format(name)
@@ -120,14 +110,6 @@ for name in pairs(types.lsp.CompletionItemKind) do
   end
 end
 
-if vim.fn.hlexists('CmpItemMenu') ~= 1 then
-  vim.cmd [[highlight default link CmpItemMenu CmpItemMenuDefault]]
-end
-
-vim.cmd [[command! CmpStatus lua require('cmp').status()]]
-
-vim.cmd [[doautocmd <nomodeline> User CmpReady]]
-
 if vim.on_key then
   vim.on_key(function(keys)
     if keys == vim.api.nvim_replace_termcodes('<C-c>', true, true, true) then
@@ -140,3 +122,7 @@ if vim.on_key then
   end, vim.api.nvim_create_namespace('cmp.plugin'))
 end
 
+vim.cmd [[command! CmpStatus lua require('cmp').status()]]
+
+vim.cmd [[doautocmd <nomodeline> User CmpReady]]
+