diff -ur fvwm-2.5.30~/libs/defaults.h fvwm-2.5.30/libs/defaults.h
--- fvwm-2.5.30~/libs/defaults.h	2009-08-02 10:58:46.000000000 -0400
+++ fvwm-2.5.30/libs/defaults.h	2010-07-12 15:22:18.964353164 -0400
@@ -25,7 +25,7 @@
 /* The "extended" buttons do not provide the full functionality because X has
  * no bit mask value for them.  Things like dragging windows don't work with
  * them. */
-#define NUMBER_OF_EXTENDED_MOUSE_BUTTONS   9
+#define NUMBER_OF_EXTENDED_MOUSE_BUTTONS   15
 #if NUMBER_OF_EXTENDED_MOUSE_BUTTONS > 31
 #error No more than 31 mouse buttons can be supported on 32 bit platforms
 #endif