Version 2.64:
+ Click on "Refresh" button in main Simple Mail window while receiving mail stops receiving.
+ "Popup" action is not included into Default filter on MacOS, because popups are not supported on MacOS
+ Improved "Send by Simple Mail" menu functionality: it's possible to select & send some text not only from internet sites, but from mail messages displayed in main Simple Mail window.
+ Changed: a contact isn't automatically added to Address Book when you send a message to him.
+ Changed: Context menu "Send by Simple Mail" shows only those contacts that are marked as "Favorite" in Address Book preferences.

Version 2.65:
+ Unread counter now shows count of unread messages in all folders except Trash
+ Possibility to turn off automatic addition of recipients to address book

Version 2.66:
+ It's possible to attach to a message multiple files at once either using "paperclip" button or by drag-n-dropping group of files to message body.
+ "Send by Simple Mail" can send selected contents of textarea/input fields
+ Shift+Del deletes without moving to Trash
+ Backspace key works the same way as Delete (delete messages)