Different problem, but your post title works here, too, so I won't start a new thread.
You use the Toolbar "Delete" button to get rid of an e-mail you don't care to save, but it doesn't go away. You have to Right-Click on the folder which holds said e-mail and select "Erase Deleted Messages" to make the offending e-mail disappear. But wait, there's more! When you do this, a sheet slides down to confirm whether you really want to erase your deleted messages. However... The message disappears AS the sheet is sliding down, so if you mistakenly hit that, too bad.
a.) Why don't messages just go away when you hit "Delete" in the toolbar, like they used to? Have I missed a setting somewhere?
and...
b.) Why have a sheet confirm whether you really want to do something, if the application's going to do it anyway?
I hope this is just a new bug which will be squashed with the .1 update and not new "features" that can't be disabled. On the flip-side, Rules work much better now.