fix menu exec point

GUI/View/Fit/FitParameterWidget.cpp

@@ -138,7 +138,7 @@ void FitParameterWidget::onFitParameterTreeContextMenu(const QPoint& point)
     }
     QMenu menu;
     menu.addAction(m_removeFitParAction);
-    menu.exec(m_treeView->mapToGlobal(point + QPoint(2, 22)));
+    menu.exec(m_treeView->viewport()->mapToGlobal(point));
     setActionsEnabled(true);
 }