diff --git a/gerbview/toolbars_gerber.cpp b/gerbview/toolbars_gerber.cpp
index 50e2fe42dd..86f4ca9470 100644
--- a/gerbview/toolbars_gerber.cpp
+++ b/gerbview/toolbars_gerber.cpp
@@ -327,7 +327,7 @@ void GERBVIEW_FRAME::updateDCodeSelectBox()
         wxASSERT_MSG( false, wxT( "Invalid units" ) );
     }
 
-    for( const auto [_, dcode] : gerber->m_ApertureList )
+    for( const auto& [_, dcode] : gerber->m_ApertureList )
     {
         wxCHECK2( dcode,continue );