Fix bug #6944.

 menu-bar.el (menu-bar-edit-menu) <"Paste">: Check selection in
 CLIPBOARD, not in PRIMARY.

lisp/ChangeLog

+2010-08-30  Eli Zaretskii  <eliz@gnu.org>
+
+	* menu-bar.el (menu-bar-edit-menu) <"Paste">: Check selection in
+	CLIPBOARD, not in PRIMARY.  (Bug#6944)
+
 2010-08-30  Stefan Monnier  <monnier@iro.umontreal.ca>
 	* emacs-lisp/smie.el (smie-indent-offset-rule): Let :parent take

lisp/menu-bar.el

@@ -463,7 +463,7 @@
 			    ;; Emacs compiled --without-x doesn't have
 			    ;; x-selection-exists-p.
 			    (and (fboundp 'x-selection-exists-p)
-				 (x-selection-exists-p))
+				 (x-selection-exists-p 'CLIPBOARD))
 			    kill-ring)
 			   (not buffer-read-only))
 	      :help ,(purecopy "Paste (yank) text most recently cut/copied")))