--- a/src/window_type.h	Thu May 15 20:51:52 2008 +0000
+++ b/src/window_type.h	Thu May 15 20:52:28 2008 +0000
@@ -94,6 +94,8 @@
 	WC_BUILD_SIGNAL,
 	WC_COMPANY_PASSWORD_WINDOW,
 	WC_OSK,
+
+	WC_INVALID = 0xFFFF
 };
 
 struct Window;