This is a very minor thing, but I'll mention it anyway because it continues to stand out to me:
When I expand a new email notification, the option to delete the message is named "TO DELETED". I understand that this is attempting to be explicit and differentiate between "move to deleted" and "delete permanently", but the phase "TO DELETED" just seems unnecessarily verbose and a little ugly. I think it would be simpler and cleaner to just name the option "DELETE". I think most AM users will understand that this will perform whatever delete action they have selected in the settings, i.e. either "move to deleted" or "delete permanently".
And another related very minor thing:
In the settings options related to deleting messages, the move to deleted option is labelled "Move to Deleted folder first". The word "first" is confusing because it implies that some other action will occur later. I think word "first" should be removed.
Thanks