patch 7.4.1695
Problem:    ":syn reset" clears the effect ":syn iskeyword". (James McCoy)
Solution:   Remove clearing the syntax keywords.
diff --git a/src/syntax.c b/src/syntax.c
index a43f4a6..31c1d0d 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -3815,6 +3815,7 @@
 
 /*
  * Handle ":syntax reset" command.
+ * It actually resets highlighting, not syntax.
  */
     static void
 syn_cmd_reset(exarg_T *eap, int syncing UNUSED)
@@ -3822,7 +3823,6 @@
     eap->nextcmd = check_nextcmd(eap->arg);
     if (!eap->skip)
     {
-	clear_string_option(&curwin->w_s->b_syn_isk);
 	set_internal_string_var((char_u *)"syntax_cmd", (char_u *)"reset");
 	do_cmdline_cmd((char_u *)"runtime! syntax/syncolor.vim");
 	do_unlet((char_u *)"g:syntax_cmd", TRUE);