updated for version 7.4.457
Problem:    Using getchar() in an expression mapping may result in
            K_CURSORHOLD, which can't be recognized.
Solution:   Add the <CursorHold> key.  (Hirohito Higashi)
diff --git a/src/misc2.c b/src/misc2.c
index 1fe0e87..d421a00 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -2471,6 +2471,7 @@
     {K_SNR,		(char_u *)"SNR"},
 #endif
     {K_PLUG,		(char_u *)"Plug"},
+    {K_CURSORHOLD,	(char_u *)"CursorHold"},
     {0,			NULL}
 };