If I’ve understood you correctly, you want to do something like this in your vimrc:
au FileType * setlocal noexpandtab
But I cannot guarantee this works (i.e., something might get triggered after this autocommand that sets expandtab). I think you could establish a buffer-local BufEnter autocommand inside the FileType autocommand, ...
Maybe there is some kind of remapping plugin for either chrome or firefox that addresses this?
Regarding Citrix, Citrix Lite and the browser, you'll have more luck asking about it on Superuser, so I suggest you post a question there for a solution from that front.
Is there any other strategy that vi users adopt?
You should be able to use Vim mappings to ...