diff --git a/graphwidget.cpp b/graphwidget.cpp
index 1e3de36..e018ff4 100644
--- a/graphwidget.cpp
+++ b/graphwidget.cpp
@@ -498,17 +498,23 @@ void GraphWidget::keyPressEvent(QKeyEvent *event)
 
 void GraphWidget::wheelEvent(QWheelEvent *event)
 {
-    if (QApplication::keyboardModifiers() == Qt::ControlModifier)
+    if (QApplication::keyboardModifiers() & Qt::ControlModifier)
     {
-        if (m_activeNode)
+        if (!m_activeNode)
         {
-            m_activeNode->setScale(pow((double)1.2, event->delta() / 120.0),
-                                   sceneRect());
+            m_parent->statusBarMsg(tr("No active node."));
+            return;
+        }
+        if (QApplication::keyboardModifiers() & Qt::ShiftModifier)
+        {
+            foreach(Node *node, m_activeNode->subtree())
+                node->setScale(pow((double)1.2, event->delta() / 120.0),
+                                 sceneRect());
         }
         else
         {
-            m_parent->statusBarMsg(tr("No active node."));
-            return;
+            m_activeNode->setScale(pow((double)1.2, event->delta() / 120.0),
+                                   sceneRect());
         }
     }
     else