diff --git a/src/generic/odcombo.cpp b/src/generic/odcombo.cpp
index fa036b21e2..c4f23b9109 100644
--- a/src/generic/odcombo.cpp
+++ b/src/generic/odcombo.cpp
@@ -477,7 +477,8 @@ void wxVListBoxComboPopup::Insert( const wxString& item, int pos )
     }
 
     m_strings.Insert(item,pos);
-    m_clientDatas.Insert(NULL, pos);
+    if ( m_clientDatas.size() >= pos )
+        m_clientDatas.Insert(NULL, pos);
 
     m_widths.Insert(-1,pos);
     m_widthsDirty = true;