There is no (obvious) equivalent of "mark all emails for deletion"
Added in version 1.0.19 was the option when you right click the message list.
ooooo .oooooo. ooooo ooooo oooooooooo. .o ooooooooo `888' d8P' `Y8b `888' `888' `888' `Y8b o888 d"""""""8' 888 888 888 888 888 888 888 888 .8' 888 888 888 888ooooo888 888 888 888 .8' 888 888 888 888 888 888 888 888 .8' 888 o `88b d88b 888 888 888 d88' 888 .8' o888ooooood8 `Y8bood8P'Ybd' o888o o888o o888bood8P' o888o .8'