diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index d71e7f9..3888d9f 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -4259,6 +4259,7 @@
 			{only available when compiled with |+mbyte|}
 	This option specifies a function that will be called to
 	activate/inactivate Input Method.
+	Does not work in the MS-Windows GUI version.
 
 	Example: >
 		function ImActivateFunc(active)
@@ -4374,6 +4375,7 @@
 			{only available when compiled with |+mbyte|}
 	This option specifies a function that is called to obtain the status
 	of Input Method.  It must return a positive number when IME is active.
+	Does not work in the MS-Windows GUI version.
 
 	Example: >
 		function ImStatusFunc()