Why is Vim executing a colorscheme file a second time if editing a Perl file?

Question

I am using Vim 7.4 through a remote PuTTY session. I set my "dracula" colorscheme in my vimrc, and then immediately after that, I remove the background setting for normal text. For Normal text, I personally prefer a solid (empty) black background to the background color that the dracula colorscheme uses. Here is the relevant code from my vimrc:

colorscheme dracula
hi Normal ctermfg=231 ctermbg=NONE cterm=NONE 

This works when I edit an HTML or text or JavaScript file, but if I edit a Perl file, the dracula colorscheme's default background is used instead. If I type :verbose hi Normal, it says "Last set from ~/.vim/bundle/vim-dracula/colors/dracula.vim" So it appears the colorscheme file is getting sourced twice: once during the normal loading of the .vimrc and another time later on. Unfortunately the :scriptnames command only shows the first time a file gets sourced. How do I find what is causing the dracula.vim file to be sourced again?

Answer 1

You can see when files are sourced with:

:set verbose=2

If that doesn't help you can try higher levels:

>= 1    When the viminfo file is read or written.
>= 2    When a file is ":source"'ed.
>= 5    Every searched tags file and include file.
>= 8    Files for which a group of autocommands is executed.
>= 9    Every executed autocommand.
>= 12   Every executed function.
>= 13   When an exception is thrown, caught, finished, or discarded.
>= 14   Anything pending in a ":finally" clause.
>= 15   Every executed Ex command (truncated at 200 characters).

Answer 2

It's not resolving the root of the problem, but you could try to override highlight groups each time the colorsheme is set:

augroup MyColorScheme
    autocmd!
    autocmd ColorScheme dracula highlight Normal ctermfg=231 ctermbg=NONE cterm=NONE
augroup END