What do you think?

[Richard Stallman]

    It might also make sense for a mouse click in the echo area to invoke
    view-messages.

What do people think of that idea?
It is hard to implement selection from the echo area,
but this comes a little close to it.


(defun mouse-drag-region-or-view-messages (event)
  "Call `mouse-drag-region', or, if in the echo area, `view-messages'.
\"The echo area\" means any inactive miniwindow.
Like mouse-drag-region, this must be bound to a button-down mouse event."
  (interactive "e")
  (let ((w (posn-window (event-start event))))
    (if (or (not (window-minibuffer-p w))
            (minibuffer-window-active-p w))
        (mouse-drag-region event)
      ;; Discard the up event.
      (read-event)
      (view-messages))))

(global-set-key [down-mouse-1] 'mouse-drag-region-or-view-messages)