diff --git a/src/controls/QskWindow.cpp b/src/controls/QskWindow.cpp
index ce84b881..58225125 100644
--- a/src/controls/QskWindow.cpp
+++ b/src/controls/QskWindow.cpp
@@ -551,7 +551,7 @@ void QskWindow::setCustomRenderMode( const char* mode )
     class RenderJob final : public QRunnable
     {
       public:
-        RenderJob( QQuickWindow* window, const QByteArray mode )
+        RenderJob( QQuickWindow* window, const QByteArray& mode )
             : m_window( window )
             , m_mode( mode )
         {
diff --git a/src/layouts/QskGridLayoutEngine.cpp b/src/layouts/QskGridLayoutEngine.cpp
index c092ddd0..f957a491 100644
--- a/src/layouts/QskGridLayoutEngine.cpp
+++ b/src/layouts/QskGridLayoutEngine.cpp
@@ -116,7 +116,7 @@ namespace
 
       private:
         inline bool setValueAt( int pos,
-            const std::function< bool( Setting& ) > modify )
+            const std::function< bool( Setting& ) >& modify )
         {
             if ( pos < 0 )
                 return false;