(#539) Check for NULL pointer when deciding what kind of range filter collection to use

As the management of override range filter collection is handled
independenly from scheduleRedraw, we must check for a valid pointer when
trying to access the override range filter

ApplicationCode/UserInterface/RiuViewerCommands.cpp

@@ -266,14 +266,7 @@ void RiuViewerCommands::displayContextMenu(QMouseEvent* event)
 
     if (menu.actions().size() > 0)
     {
-//        event->accept();
-        QAction* act = menu.exec(event->globalPos());
-/*
-        if (act)
-        {
-            cvf::Trace::show("Jadda");
-        }
-*/
+        menu.exec(event->globalPos());
     }
 }