Should I Be Seeing Vendor Prefixes?

[preston206]

Hello, I'm new to using Slater. I have it all set up and almost everything seems to be working. However, I'm not seeing vendor prefixes. Should I be? I thought those were a part of PostCSS?

For example, if I add this:
display: flex

I should see this:

display: -webkit-box;
display: -ms-flexbox;
display: flex;

If it's not a feature, sorry, pardon my newbie-ness. Thanks for any help. Great tool by the way. It's going to help out a lot!