– HIG states, dont change the tool button labels. That is one reason, why “Delete” / “Undelete” and “Junk” / “Not Junk” cant be merged.
There was some proposal to make spam assasin learn as ham (Not a spam). Both Junk and Not_Junk button has to be present for that. Atleast It was merged in early 2.14 cycle and reverted for above reasons.
– “Delete” option in context menu for a deleted message was a due to bug 254770 You can reopen and put down your views there
– I strongly agree to the jumping message selection in threaded view. Please file a bug, and put down your expectation, we would be happy to fix it.