diff --git a/autoload/airline/extensions/tagbar.vim b/autoload/airline/extensions/tagbar.vim
index bf7efee..4b51787 100644
--- a/autoload/airline/extensions/tagbar.vim
+++ b/autoload/airline/extensions/tagbar.vim
@@ -16,11 +16,17 @@ function! airline#extensions#tagbar#inactive_apply(...)
   endif
 endfunction
 
+function! airline#extensions#tagbar#currenttag()
+  if get(w:, 'airline_active', 0)
+    return tagbar#currenttag('%s', '')
+  endif
+  return ''
+endfunction
+
 function! airline#extensions#tagbar#init(ext)
   call a:ext.add_inactive_statusline_func('airline#extensions#tagbar#inactive_apply')
   let g:tagbar_status_func = 'airline#extensions#tagbar#get_status'
 
-  let g:airline_parts.tagbar = '%(%{get(w:,"airline_active",0) ? tagbar#currenttag("%s","") : ""} '
-        \ .g:airline_right_alt_sep.' %)'
+  let g:airline_parts.tagbar = 'airline#extensions#tagbar#currenttag'
 endfunction
 
diff --git a/plugin/airline.vim b/plugin/airline.vim
index e5b812b..179446f 100644
--- a/plugin/airline.vim
+++ b/plugin/airline.vim
@@ -83,11 +83,11 @@ function! s:init()
     call airline#util#define_section('a', ['mode', 'paste', 'iminsert'])
     call airline#util#define_section('b', ['hunks', 'branch'])
     call airline#util#define_section('c', ['%<', 'file'])
-    call s:check_defined('g:airline_section_gutter', ' '.(g:airline_parts.readonly).'%=')
-    call s:check_defined('g:airline_section_x', (g:airline_parts.tagbar).'%{&filetype}')
-    call s:check_defined('g:airline_section_y', g:airline_parts.ffenc)
-    call s:check_defined('g:airline_section_z', '%3p%% %{g:airline_symbols.linenr} %3l:%3c ')
-    call s:check_defined('g:airline_section_warning', (g:airline_parts.syntastic).(g:airline_parts.whitespace))
+    call airline#util#define_section('gutter', ['readonly', '%='])
+    call airline#util#define_section('x', ['tagbar', '%{&filetype}'])
+    call airline#util#define_section('y', ['ffenc'])
+    call airline#util#define_section('z', ['%3p%% %{g:airline_symbols.linenr} %3l:%3c '])
+    call airline#util#define_section('warning', ['syntastic', 'whitespace'])
 
     let s:airline_theme_defined = exists('g:airline_theme')
     if s:airline_theme_defined || !airline#switch_matching_theme()