Today, I renamed an existing notebook in Penultimate. Unfortunately, I chose a name of an already existing notebook, earlier created in EN. As a result, the notebook disappeared from the PU overview of notebooks. This is counterintuitive behaviour: a 'rename' suddenly seems to delete (or at least hide) an existing notebook. And I did not immediately realise what just had happened, as there was not even a warning message informing me of the duplicate notebook name.
I guess this is a bug? It could hardly be considered a feature...
What would work best in my opinion: let PU show all EN