diff --git a/src/gtk/choice.cpp b/src/gtk/choice.cpp
index ff73d14474..34bd9964dd 100644
--- a/src/gtk/choice.cpp
+++ b/src/gtk/choice.cpp
@@ -181,8 +181,12 @@ void wxChoice::DoDeleteOneItem(unsigned int n)
     GtkTreeModel* model = gtk_combo_box_get_model( combobox );
     GtkListStore* store = GTK_LIST_STORE(model);
     GtkTreeIter iter;
-    gtk_tree_model_iter_nth_child( model, &iter,
-                                   NULL, (gint) n );
+    if ( !gtk_tree_model_iter_nth_child(model, &iter, NULL, n) )
+    {
+        // This is really not supposed to happen for a valid index.
+        wxFAIL_MSG(wxS("Item unexpectedly not found."));
+        return;
+    }
     gtk_list_store_remove( store, &iter );
 
     m_clientData.RemoveAt( n );