Selection changes in revno 100822

[Eli Zaretskii]

I'm studying the changes in how selections behave that were made in
revno 100822, and I have a couple of questions:

  . Why was mouse-drag-copy-region changed to default to nil?  This
    variable doesn't seem to be related to selections, but rather to
    the kill ring.

  . The change in binding mouse-2 to mouse-yank-primary instead of
    mouse-yank-at-point, in addition to referencing only the primary
    selection, means one more change: mouse-2 no longer yanks the last
    kill, except through the primary selection.  Is this change in
    behavior intentional, and if so, what is the reason behind this
    change?