runtime(optwin): add missing values for tabpanel option

closes: #17685

Signed-off-by: RestorerZ <restorer@mail2k.ru>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/optwin.vim b/runtime/optwin.vim
index 9197457..0158f97 100644
--- a/runtime/optwin.vim
+++ b/runtime/optwin.vim
@@ -1,7 +1,7 @@
 " These commands create the option window.
 "
 " Maintainer:	The Vim Project <https://github.com/vim/vim>
-" Last Change:	2025 Jul 02
+" Last Change:	2025 Jul 05
 " Former Maintainer:	Bram Moolenaar <Bram@vim.org>
 
 " If there already is an option window, jump to that one.
@@ -1472,8 +1472,11 @@
 endif
 if has("tabpanel")
   call <SID>AddOption("showtabpanel", gettext("0, 1 or 2; when to use the tabpanel"))
+  call <SID>OptionG("showtabpanel", &showtabpanel)
   call <SID>AddOption("tabpanel", gettext("custom tab pages in tabpanel"))
+  call <SID>OptionG("tabpanel", &tabpanel)
   call <SID>AddOption("tabpanelopt", gettext("options for using tabpanel"))
+  call <SID>OptionG("tabpanelopt", &tabpanelopt)
 endif
 
 set cpo&vim