hi, the ask anytime option for cookies was removed in firefox 44, which
was supposed to happen for a long time (bug 606655).
i would recommend the following setup instead: in the custom history
options choose "keep until i close firefox" as a default option & set
exceptions for the few sites where you want stay logged-in across
sessions. this way you'll have less work to do over all and a
privacy-minded setup after all.
or as an alternative you could also take a look at an extension like
Lots of people complain about this. Consider to keep the code for
cookies "ask me every time" from Firefox 43 for IceCat 45.