patch 9.1.1403: expansion of 'tabpanelopt' value adds wrong values

Problem:  expansion of 'tabpanelopt' value adds wrong values
          (Shane-XB-Qian, after v9.1.1391)
Solution: update tabpanelopt expansion function and expand only valid
          values (Hirohito Higashi)

related: #17263
closes: #17359

Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/optiondefs.h b/src/optiondefs.h
index cb4376c..5d9f388 100644
--- a/src/optiondefs.h
+++ b/src/optiondefs.h
@@ -2537,7 +2537,8 @@
     {"tabpanel",  "tpl",    P_STRING|P_VI_DEF|P_RALL,
 			    (char_u *)&p_tpl, PV_NONE, NULL, NULL,
 			    {(char_u *)"", (char_u *)0L} SCTX_INIT},
-    {"tabpanelopt","tplo",  P_STRING|P_VI_DEF|P_ONECOMMA|P_NODUP,
+    {"tabpanelopt","tplo",  P_STRING|P_ALLOCED|P_VI_DEF|P_ONECOMMA|P_COLON
+								    |P_NODUP,
 			    (char_u *)&p_tplo, PV_NONE, did_set_tabpanelopt,
 			    expand_set_tabpanelopt,
 			    {(char_u *)"", (char_u *)0L}