There is an annoying behaviour of the buttons below the e-mail "Message list" pane. These buttons exchange places when each message is selected. So, if you just want to press "Archive", when trying to do that, the button moves and gives place to "Junk"... and then you accidentally press it, regret it, and then go search the message to un-junk it and finally archive it.
What I suggest is that the buttons be always located at the same location. If, for some reason, the button is not required or applicable for that particular message, then just make it inactive and change its color to gray.
