diff --git a/src/diff.c b/src/diff.c
index 7170835..b28e127 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -1078,6 +1078,9 @@
 	curbuf = curwin->w_buffer;
 	set_string_option_direct((char_u *)"fdm", -1, (char_u *)"diff",
 							  OPT_LOCAL|OPT_FREE);
+# ifdef FEAT_EVAL
+	set_option_scriptID((char_u *)"fdm", current_SID);
+# endif
 	curwin = old_curwin;
 	curbuf = curwin->w_buffer;
 	wp->w_p_fdc = 2;
@@ -1125,6 +1128,9 @@
 	    curbuf = curwin->w_buffer;
 	    set_string_option_direct((char_u *)"fdm", -1,
 				      (char_u *)"manual", OPT_LOCAL|OPT_FREE);
+# ifdef FEAT_EVAL
+	    set_option_scriptID((char_u *)"fdm", current_SID);
+# endif
 	    curwin = old_curwin;
 	    curbuf = curwin->w_buffer;
 	    wp->w_p_fdc = 0;