[vtkusers] Blocking 'Q' and 'E' keys

[Nick Gnedin]

Here is a snippet from vtkRenderWindowInteractor.cpp. I think if you
have an empty observer for vtkCommand::ExitEvent, the application
would not terminate.


void vtkRenderWindowInteractor::ExitCallback()
{
  if (this->HasObserver(vtkCommand::ExitEvent))
    {
    this->InvokeEvent(vtkCommand::ExitEvent,NULL);
    }
  else
    {
    this->TerminateApp();
    }
}