diff --git a/common/preview_items/polygon_geom_manager.cpp b/common/preview_items/polygon_geom_manager.cpp
index bb87e11774..3b4cdb2b8d 100644
--- a/common/preview_items/polygon_geom_manager.cpp
+++ b/common/preview_items/polygon_geom_manager.cpp
@@ -146,7 +146,7 @@ void POLYGON_GEOM_MANAGER::Reset()
 }
 
 
-SHAPE_LINE_CHAIN build45DegLeader( const VECTOR2I& aEndPoint, SHAPE_LINE_CHAIN aLastPoints )
+static SHAPE_LINE_CHAIN build45DegLeader( const VECTOR2I& aEndPoint, SHAPE_LINE_CHAIN aLastPoints )
 {
     if( aLastPoints.PointCount() < 1 )
         return SHAPE_LINE_CHAIN();