copy-paste problem

[bcjrstan]

hi,
I use Emacs 22.0.99 ,have  problem in copy-paste from/to emacs.
my .emacs part concerning x11-copy-paste part
(setq x-select-enable-clipboard t)
(setq interprogram-paste-function 'x-cut-buffer-or-selection-value)

Select a text in X11 application whatever and copy it to the
clipboard, then copy it in Emacs window, using the middle mouse button
or Ctrl-y, it's ok.
 *but* I can do it *only* untill I cut a text in Emacs window (mouse
or keyboard), after that, in *no* way I can copy and paste a text from
another window: it is always the last selected text in Emacs which can
copied.... That's very strange, it is as if there were two clipboards,
one I can use *out* of Emacs, and one in Emacs, but I cannot  go from
an application to Emacs....
and how to solve this ?
Thank you!!