CSI ?2004h not set if external shell command is run first

[ColMelvin]

If any shell cmd (:!) is run before let &t_ti .= ..., then the CSI ?2004h escape code will not be sent to the terminal, making this plugin a nop. However, if the shell command appears after let &t_te .= ..., there are no issues.

Reproduction steps:

echo 'silent !true' > ~/.vimrc
cat bracketed-paste.vim >> ~/.vimrc
vim
#Attempt to paste contents that need "set paste" while in insert mode

VIM - Vi IMproved 7.4
Commit: 96451c8

[ColMelvin]

If this can't be fixed, it would be nice to fall back to t_SI and t_EI so at least insert mode works. Sadly, I haven't found a straightforward way to detect if a shell command has already been run.