diff --git a/autoload/color_helper.vim b/autoload/color_helper.vim
index 7648eff..7537253 100644
--- a/autoload/color_helper.vim
+++ b/autoload/color_helper.vim
@@ -1,16 +1,6 @@
 " Author:   Nate Kane <nathanaelkane AT gmail DOT com>
 " Homepage: http://github.com/nathanaelkane/vim-indent-guides
 
-"
-" Regex pattern for a hex color.
-"
-" Example matches:
-" - '#123ABC'
-" - '#ffffff'
-" - '#000000'
-"
-let s:hex_color_pattern = '#[0-9A-Fa-f]\{6\}'
-
 "
 " Return hex string equivalent to given decimal string or number.
 "
@@ -49,7 +39,7 @@ endfunction
 function! color_helper#hex_color_to_rgb(hex_color)
   let l:rgb = []
 
-  if matchstr(a:hex_color, s:hex_color_pattern) == a:hex_color
+  if a:hex_color =~ g:indent_guides_hex_color_pattern
     let l:red   = color_helper#hex_to_dec(strpart(a:hex_color, 1, 2))
     let l:green = color_helper#hex_to_dec(strpart(a:hex_color, 3, 2))
     let l:blue  = color_helper#hex_to_dec(strpart(a:hex_color, 5, 2))
diff --git a/autoload/indent_guides.vim b/autoload/indent_guides.vim
index 636df4e..366e3f9 100644
--- a/autoload/indent_guides.vim
+++ b/autoload/indent_guides.vim
@@ -2,29 +2,37 @@
 " Homepage: http://github.com/nathanaelkane/vim-indent-guides
 
 "
-" Toggles the indent guides on and off for all buffers.
+" Toggles the indent guides on and off.
 "
 function! indent_guides#toggle()
   call indent_guides#init_matches()
+
   if empty(w:indent_guides_matches)
     call indent_guides#enable()
-
-    " DEBUG
-    "echo 'enable'
   else
     call indent_guides#disable()
-
-    " DEBUG
-    "echo 'disable'
   endif
 endfunction
 
 "
-" Enables the indent guides for all buffers.
+" Called from autocmds, keeps indent guides enabled or disabled when entering
+" other buffers and windows.
+"
+function! indent_guides#process_autocmds()
+  if g:indent_guides_autocmds_enabled
+    call indent_guides#enable()
+  else
+    call indent_guides#disable()
+  end
+endfunction
+
+"
+" Enables the indent guides for the current buffer and any other buffer upon
+" entering it.
 "
 function! indent_guides#enable()
-  call indent_guides#init_matches()
-  call indent_guides#disable()
+  let g:indent_guides_autocmds_enabled = 1
+  call indent_guides#clear_matches()
 
   if g:indent_guides_auto_colors
     call indent_guides#highlight_colors()
@@ -41,59 +49,61 @@ function! indent_guides#enable()
 
     " define the higlight pattern and add to list
     call add(w:indent_guides_matches, matchadd(group, pattern))
-
-    if g:indent_guides_debug
-      echo "matchadd ('" . group . "', '" . pattern . "')"
-    end
   endfor
-
-  " DEBUG
-  "echo w:indent_guides_matches
 endfunction
 
 "
-" Disables the indent guides for all buffers.
+" Disables the indent guides for the current buffer and any other buffer upon
+" entering it.
 "
 function! indent_guides#disable()
+  let g:indent_guides_autocmds_enabled = 0
+  call indent_guides#clear_matches()
+endfunction
+
+"
+" Clear all highlight matches for the current window.
+"
+function! indent_guides#clear_matches()
   call indent_guides#init_matches()
-
   if !empty(w:indent_guides_matches)
-
-    " DEBUG
-    "echo w:indent_guides_matches
-
     let index = 0
     for match_id in w:indent_guides_matches
       call matchdelete(match_id)
       call remove(w:indent_guides_matches, index)
       let index += index
     endfor
-    "call filter(w:indent_guides_matches, 0)
   endif
 endfunction
 
 "
 " Automagically calculates and defines the indent highlight colors.
 "
+" NOTE: Does not work when color names are used instead of hex colors.
+"       Eg. 'guibg=#FFFFFF' works, but 'guibg=green' doesn't.
+"
 function! indent_guides#highlight_colors()
   if g:indent_guides_auto_colors
     " capture the backgroud color from the normal highlight
     let hi_normal       = indent_guides#capture_highlight('normal')
-    let hi_normal_guibg = matchstr(hi_normal, 'guibg=\zs#[0-9A-Fa-f]\{6\}\ze')
+    let pattern         = 'guibg=\zs'. g:indent_guides_hex_color_pattern . '\ze'
+    let hi_normal_guibg = matchstr(hi_normal, pattern)
 
-    " calculate the highlight background colors
-    let hi_odd_bg  = indent_guides#lighten_or_darken_color(hi_normal_guibg)
-    let hi_even_bg = indent_guides#lighten_or_darken_color(hi_odd_bg)
+    if hi_normal_guibg =~ g:indent_guides_hex_color_pattern
+      " calculate the highlight background colors
+      let hi_odd_bg  = indent_guides#lighten_or_darken_color(hi_normal_guibg)
+      let hi_even_bg = indent_guides#lighten_or_darken_color(hi_odd_bg)
 
-    " define the new highlights
-    exe "hi IndentGuidesOdd  guibg=" . hi_odd_bg
-    exe "hi IndentGuidesEven guibg=" . hi_even_bg
+      " define the new highlights
+      exe "hi IndentGuidesOdd  guibg=" . hi_odd_bg
+      exe "hi IndentGuidesEven guibg=" . hi_even_bg
+    end
   endif
 endfunction
 
 "
-" Takes a color and darkens or lightens it depending on whether a dark or
-" light colorscheme is being used.
+" Takes a color and darkens or lightens it depending on whether a dark or light
+" colorscheme is being used.
 "
 function! indent_guides#lighten_or_darken_color(color)
     let percent = g:indent_guides_auto_colors_change_percent
@@ -106,10 +116,10 @@ function! indent_guides#lighten_or_darken_color(color)
 endfunction
 
 "
-" Captures and returns the output of highlight group definitions
+" Captures and returns the output of highlight group definitions.
 "
 " Example: indent_guides#capture_highlight('normal')
-" Returns: 'Normal xxx guifg=#323232 guibg=#ffffff font=DejaVu Sans Mono 9'
+" Returns: 'Normal xxx guifg=#323232 guibg=#ffffff
 "
 function! indent_guides#capture_highlight(group_name)
     redir => output
@@ -119,9 +129,11 @@ function! indent_guides#capture_highlight(group_name)
     return output
 endfunction
 
+"
+" Init the w:indent_guides_matches variable.
+"
 function! indent_guides#init_matches()
   let w:indent_guides_matches =
-    \ exists('w:indent_guides_matches') ?
-    \ w:indent_guides_matches : []
+    \ exists('w:indent_guides_matches') ? w:indent_guides_matches : []
 endfunction
 
diff --git a/plugin/indent_guides.vim b/plugin/indent_guides.vim
index 1092f1e..f8f454d 100644
--- a/plugin/indent_guides.vim
+++ b/plugin/indent_guides.vim
@@ -35,6 +35,24 @@ let g:indent_guides_debug =
   \ exists('g:indent_guides_debug') ?
   \ g:indent_guides_debug : 0
 
+let g:indent_guides_autocmds_enabled = 0
+
+"
+" Regex pattern for a hex color.
+"
+" Example matches:
+" - '#123ABC'
+" - '#ffffff'
+" - '#000000'
+"
+let g:indent_guides_hex_color_pattern = '#[0-9A-Fa-f]\{6\}'
+
 " Default mapping
 nmap <Leader>ig :IndentGuidesToggle<CR>
 
+" Auto commands
+augroup indent_guides
+  autocmd!
+  autocmd BufEnter,WinEnter * call indent_guides#process_autocmds()
+augroup END
+