I have both the beta Thunderbird for Android and the k9 clients on my phone but hadn't realised they were not interchangable, so I got a surprise when I opened via the blue icon and deleted an email and there was no 'are you sure you want to delete' or deletion options dialogue on the thunderbird version. The K9 still asks to confirm delete, but the thunderbird only has three options in the settings and I cant find any setting to turn on the dialogue.

If I'm not missing something (maybe I missed an update), I suggest this needs copying over from K9.