I normally have my emails shown in card view sorted by date and in descending view so that newest emails are at the top. If I sort by something else, like Sender and then sort back to Date, Thunderbird defaults to ascending view and I always have to open sort again (because it closes once you choose date) and then select descending. My suggestion is either have Thunderbird sort stay open so both sort type and sort order can be chosen (use an OK button or similar), or have Thunderbird retain the ascending/descending preference unchanged.