(HTTPSE 4.0.3 + FF 36.0.1) Enable clicking "Block all HTTP requests" without reload
Switching "Block all HTTP requests" immediately reloads the current page, although sometimes it might be useful to actuate the change only on subsequent pages. Example: poczta.wp.pl (mixed content) -- you cannot log out with the switch on.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information