diff --git a/runtime/optwin.vim b/runtime/optwin.vim
index db433c6..04fe3b3 100644
--- a/runtime/optwin.vim
+++ b/runtime/optwin.vim
@@ -343,6 +343,9 @@
 call <SID>AddOption("scroll", gettext("number of lines to scroll for CTRL-U and CTRL-D"))
 call append("$", "\t" .. s:local_to_window)
 call <SID>OptionL("scr")
+call <SID>AddOption("smoothscroll", gettext("scroll by screen line"))
+call append("$", "\t" .. s:local_to_window)
+call <SID>BinOptionL("sms")
 call <SID>AddOption("scrolloff", gettext("number of screen lines to show around the cursor"))
 call append("$", " \tset so=" . &so)
 call <SID>AddOption("wrap", gettext("long lines wrap"))