diff --git a/src/app/qgsfieldsproperties.cpp b/src/app/qgsfieldsproperties.cpp
index 6055ed48d7c..291d0ecfda3 100644
--- a/src/app/qgsfieldsproperties.cpp
+++ b/src/app/qgsfieldsproperties.cpp
@@ -249,6 +249,7 @@ void QgsFieldsProperties::setRow( int row, int idx, const QgsField& field )
     QWidget* expressionWidget = new QWidget;
     expressionWidget->setLayout( new QHBoxLayout );
     QToolButton* editExpressionButton = new QToolButton;
+    editExpressionButton->setProperty( "Index", mLayer->fields().fieldOriginIndex( idx ) );
     editExpressionButton->setIcon( QgsApplication::getThemeIcon( "/mIconExpression.svg" ) );
     connect( editExpressionButton, SIGNAL( clicked() ), this, SLOT( updateExpression() ) );
     expressionWidget->layout()->setContentsMargins( 0, 0, 0, 0 );