When I run Tor Browser in a whonix-ws (as opposed to debian-8 or fedora-23) AppVM, the small blue HTTPS Everywhere icon, usually placed to the right of the search bar, is missing. Instead, it appears inside the drawer that opens when the menu button (also to the right of the search bar) is pressed.

This happens both with the Tor Browser provided by Whonix (via the torbrowser command) and a manually downloaded and extracted Tor Browser.