--- a/cygwin.rst	Sun Aug 01 16:40:15 2010 +0300
+++ b/cygwin.rst	Sun Aug 01 16:41:40 2010 +0300
@@ -53,3 +53,7 @@
 * Running X Window.
 
   $ XWin -multiwindow&
+
+To start X application you must set 'DISPLAY':
+
+  $ DISPLAY=:0 xterm&