[vim] Change the default layout to use popup window

The new default is

  { 'window' : { 'width': 0.9, 'height': 0.6, 'highlight': 'Normal' } }

The default highlight group for the border of the popup window is
'Comment', but 'Normal' seems to be a safer choice.

If you prefer the previous default, add this to your Vim configuration file:

  let g:fzf_layout = { 'down': '40%' }

(fzf will fall back to this if popup window is not supported)

README-VIM.md

@@ -127,8 +127,9 @@ let g:fzf_action = {
   \ 'ctrl-v': 'vsplit' }
 
 " Default fzf layout
-" - down / up / left / right
+" - down / up / left / right / window
 let g:fzf_layout = { 'down': '40%' }
+let g:fzf_layout = { 'window': { 'width': 0.9, 'height': 0.6 } }
 
 " You can set up fzf window using a Vim command (Neovim or latest Vim 8 required)
 let g:fzf_layout = { 'window': 'enew' }
@@ -416,8 +417,8 @@ When fzf starts in a terminal buffer, the file type of the buffer is set to
 `fzf`. So you can set up `FileType fzf` autocmd to customize the settings of
 the window.
 
-For example, if you use the default layout (`{'down': '40%'}`) on Neovim, you
-might want to temporarily disable the statusline for a cleaner look.
+For example, if you use a non-popup layout (e.g. `{'down': '40%'}`) on Neovim,
+you might want to temporarily disable the statusline for a cleaner look.
 
 ```vim
 if has('nvim') && !exists('g:fzf_layout')

doc/fzf.txt

@@ -154,8 +154,9 @@ Examples~
       \ 'ctrl-v': 'vsplit' }
 
     " Default fzf layout
-    " - down / up / left / right
+    " - down / up / left / right / window
     let g:fzf_layout = { 'down': '~40%' }
+    let g:fzf_layout = { 'window': { 'width': 0.9, 'height': 0.6 } }
 
     " You can set up fzf window using a Vim command (Neovim or latest Vim 8 required)
     let g:fzf_layout = { 'window': 'enew' }
@@ -426,8 +427,9 @@ When fzf starts in a terminal buffer, the file type of the buffer is set to
 `fzf`. So you can set up `FileType fzf` autocmd to customize the settings of
 the window.
 
-For example, if you use the default layout (`{'down': '~40%'}`) on Neovim, you
-might want to temporarily disable the statusline for a cleaner look.
+For example, if you use a non-popup layout (e.g. `{'down': '40%'}`) on
+Neovim, you might want to temporarily disable the statusline for a cleaner
+look.
 >
     if has('nvim') && !exists('g:fzf_layout')
       autocmd! FileType fzf

plugin/fzf.vim

@@ -115,7 +115,6 @@ function! s:fzf_tempname()
   return s:fzf_call('tempname')
 endfunction
 
-let s:default_layout = { 'down': '~40%' }
 let s:layout_keys = ['window', 'tmux', 'up', 'down', 'left', 'right']
 let s:fzf_go = s:base_dir.'/bin/fzf'
 let s:fzf_tmux = s:base_dir.'/bin/fzf-tmux'
@@ -123,6 +122,16 @@ let s:fzf_tmux = s:base_dir.'/bin/fzf-tmux'
 let s:cpo_save = &cpo
 set cpo&vim
 
+function! s:popup_support()
+  return has('nvim') ? has('nvim-0.4') : has('popupwin') && has('patch-8.2.191')
+endfunction
+
+function! s:default_layout()
+  return s:popup_support()
+        \ ? { 'window' : { 'width': 0.9, 'height': 0.6, 'highlight': 'Normal' } }
+        \ : { 'down': '~40%' }
+endfunction
+
 function! fzf#install()
   if s:is_win && !has('win32unix')
     let script = s:base_dir.'/install.ps1'
@@ -325,7 +334,7 @@ function! fzf#wrap(...)
     if !exists('g:fzf_layout') && exists('g:fzf_height')
       let opts.down = g:fzf_height
     else
-      let opts = extend(opts, s:validate_layout(get(g:, 'fzf_layout', s:default_layout)))
+      let opts = extend(opts, s:validate_layout(get(g:, 'fzf_layout', s:default_layout())))
     endif
   endif
 
@@ -658,7 +667,7 @@ function! s:split(dict)
   try
     if s:present(a:dict, 'window')
       if type(a:dict.window) == type({})
-        if !(has('nvim') ? has('nvim-0.4') : has('popupwin') && has('patch-8.2.191'))
+        if !s:popup_support()
           throw 'Nvim 0.4+ or Vim 8.2.191+ with popupwin feature is required for pop-up window'
         end
         call s:popup(a:dict.window)