Bug fix in the ALT selection mode in the TreeView.

GUI_main/UIDataWidget.cpp

@@ -115,7 +115,7 @@ void UIDataWidget::updateSelection( GenericUIData *d, Qt::KeyboardModifiers modi
 
 void UIDataWidget::mouseReleaseEvent( QMouseEvent *evt )
 {
-    if( QApplication::keyboardModifiers() & Qt::AltModifier )
+    if( evt->button() == Qt::LeftButton  &&  (QApplication::keyboardModifiers() & Qt::AltModifier) )
     {
         GenericUIData *m = ((UIDataWidgetItem*) itemAt(evt->pos()))->getUIData();
         if( m )
@@ -135,8 +135,8 @@ void UIDataWidget::mouseReleaseEvent( QMouseEvent *evt )
             } );
         }
     }
-
-    QTreeWidget::mouseReleaseEvent( evt );
+    else
+        QTreeWidget::mouseReleaseEvent( evt );
 }