message: fixup a crash with new light editor
  If you opened light editor with scivis, whichLight would
  be at its default of -1.
diff: @@ -1059,6 +1059,10 @@ void MainWindow::buildWindowLightEditor()
  lightTypeUI_callback,
  nullptr,
  g_lightTypes.size());
  + if (whichLightType < 0 or whichLightType > g_lightTypes.size())
  + {
  + return;
  + }
  static bool lightNameWarning = false;
  static char lightName[64] = "";
  