diff --git a/lcl/include/customcombobox.inc b/lcl/include/customcombobox.inc
index c50588ed16..b73ec46f17 100644
--- a/lcl/include/customcombobox.inc
+++ b/lcl/include/customcombobox.inc
@@ -38,7 +38,7 @@ begin
   // and use the interface based list
   FItems := NewStrings;
 
-  if FItemIndex <> -1 then
+  if (FItemIndex > -1) and (FItemIndex < FItems.Count) then
     TWSCustomComboBoxClass(WidgetSetClass).SetItemIndex(Self, FItemIndex);
   TWSCustomComboBoxClass(WidgetSetClass).SetStyle(Self, FStyle);
   TWSCustomComboBoxClass(WidgetSetClass).SetArrowKeysTraverseList(Self, FArrowKeysTraverseList);