kill-ring-save, x-select-enable-primary and Date header

[pmlists@free.fr (Peter Münster)]

Hello,

With the latest emacs and gnus versions, the kill-ring-save (M-w)
doesn't work in the article buffer: instead of copying from mark to
point, the region between mark and the line after the Date header is
copied.

For example: when yanking, I get 
"Organization: Теодор Златанов @ Cienfuegos"
instead of
"On Fri, 13 May 2011 15:09:49 -0400 Dan Christensen <jdc@uwo.ca> wrote:"

Steps to reproduce the problem:
- set x-select-enable-primary to "t"
  (I need that, because I often select a region with the mouse in
  firefox or xterm, and when "nil", I cannot yank the selection with C-y)
- let elapse at least one second between placing the mark (C-SPC) and
  pressing M-w

How can solve this problem (while keeping the dynamic Date header)?

TIA for any hint!

-- 
           Peter