diff --git a/src/gui/qgspropertyoverridebutton.cpp b/src/gui/qgspropertyoverridebutton.cpp
index 3394f1c065df..a117fc2e658a 100644
--- a/src/gui/qgspropertyoverridebutton.cpp
+++ b/src/gui/qgspropertyoverridebutton.cpp
@@ -263,6 +263,12 @@ void QgsPropertyOverrideButton::mouseReleaseEvent( QMouseEvent *event )
     return;
   }
 
+  if ( event->button() == Qt::MiddleButton )
+  {
+    showExpressionDialog();
+    return;
+  }
+
   // pass to default behavior
   QToolButton::mousePressEvent( event );
 }