diff -up extrema-4.4.5/src/wxForms/VisualizationWindow.cpp.wx3 extrema-4.4.5/src/wxForms/VisualizationWindow.cpp
--- extrema-4.4.5/src/wxForms/VisualizationWindow.cpp.wx3	2018-08-28 23:17:35.516411081 -0400
+++ extrema-4.4.5/src/wxForms/VisualizationWindow.cpp	2018-08-28 23:27:22.138827850 -0400
@@ -302,6 +302,7 @@ void VisualizationWindow::SavePS( wxStri
 
 void VisualizationWindow::ResetPages()
 {
+  if ( !notebook_ ) return;
   GraphicsPage *currentPage = static_cast<GraphicsPage*>(notebook_->GetCurrentPage());
   Layout();