diff --git a/src/engine_gui.cpp b/src/engine_gui.cpp
index c9bd056505..edbc0a8abf 100644
--- a/src/engine_gui.cpp
+++ b/src/engine_gui.cpp
@@ -214,9 +214,9 @@ void EngList_Sort(GUIEngineList *el, EngList_SortTypeFunction compare)
  */
 void EngList_SortPartial(GUIEngineList *el, EngList_SortTypeFunction compare, uint begin, uint num_items)
 {
+	if (num_items < 2) return;
 	assert(begin < el->Length());
 	assert(begin + num_items <= el->Length());
-	if (num_items < 2) return;
 	qsort(el->Get(begin), num_items, sizeof(*el->Begin()), compare);
 }