I am an old IT guy, have used email for many years, from character terminals to pc to smartphone. I have used Thunderbird for many years, and I actively promote it to many people, including non-IT people. I understand why keyboard shortcuts exist, but it is very confusing to explain unintended behaviours caused simply by the user's cursor being at the wrong place. I am very careful myself, but I also have had to search the ends of the earth to find inadvertently deleted/archived/threaded messages. Particularly if Thunderbird wishes to remain relevant in the future, which means relevant to younger folk who, unlike us, did not grow up on character-based applications, it's time to move to the future and ditch most of the keyboard shortcuts, or at least to include a configuration option to change or disable most of them, most urgently the single-letter shortcuts, which can easily be triggered inadvertently. I'm sure some long term users would object strenuously to getting rid totally, so let it be a config option. The fact that the message boards are not full of complaints does not mean people are not annoyed, just accepting of this annoyance because otherwise Thunderbird is so much better than any other client!