This is a mirror of http://www.vim.org/scripts/script.php?script_id=3383

DESCRIPTION
This plugin indicates the state of the buffer (modified, readonly,
unmodifiable, special non-file "scratch") / window (is preview window) by
changing the highlighting of the window's status line. It defines additional
StatusLine... / StatusLine...NC highlight groups that are customizable and by
default use different colors to differentiate the buffer states. 

An example screenshot can be found at
    http://ingo-karkat.de/swdev/vim/StatusLineHighlight.png

HOW IT WORKS
Using different colors for the status line is trickier than it seems: Though
the 'statusline' setting supports inline expressions via %{expr}, the returned
text is taken as-is; highlight items %#hlgroup# and #* are not evaluated, only
printed as text. Evaluation does happen when one %!expr is used, but the
expression seems to be evaluated only once for a complete screen redraw cycle,
not for each individual status line, so one cannot use it to set different
highlightings for different status lines. 

Therefore, this plugin sets up autocmds that continually adapt buffer-local
'statusline' settings (which prepend the highlight group to the (mostly)
global setting (though local 'statusline' settings set by ftplugins are kept,
too)). 

USAGE
This plugin does not introduce any commands or mappings. Just observe the
changed status line colors, e.g. when using :view, :pedit, :help, etc. 

You immediately see that a buffer is read-only because its status line is
gray, not black; unmodifiable buffers are even "more" gray. Unsaved, modified
buffers are indicated via a dark-red status line. Special windows like the
command and quickfix windows, as well as many "scratch" buffers used by
plugins are shown in dark blue. The preview window is now also easy to find,
because it has a blue status line.