--- a/src/newgrf_callbacks.h	Sat Mar 08 18:32:01 2008 +0000
+++ b/src/newgrf_callbacks.h	Mon Mar 10 15:31:07 2008 +0000
@@ -210,6 +210,11 @@
 
 	/** Customize the output cargo types of a newly build industry. */
 	CBID_INDUSTRY_OUTPUT_CARGO_TYPES     = 0x14C,
+
+	/* ATTENTION:
+	 * When adding new callbacks and their result is 15bit, add them to newgrf_spritegroup.cpp:Is8BitCallback().
+	 * It does not harm to add them there though they are not implemented. But it does harm if they get forgotton.
+	 */
 };
 
 /**