Problem with leave=False

[astyonax]

Running tqdm_notebook as

for j in tqdm_notebook(range(3), leave=False):
  print j

after saving and reopening the notebook I get this message:

A Jupyter widget could not be displayed because the widget state could not be found. This could happen if the kernel storing the widget is no longer available, or if the widget state was not saved in the notebook. You may be able to create the widget by running the appropriate cells.

which is logically correct because I opted for not leaving the widget visible.
But the message should not be there too. Is this a tqdm issue or a jupyter one?

jupyer: 5.2.2
tqdm: 4.19.4

[casperdcl]

@astyonax the real maintained repo is at https://github.com/tqdm/tqdm.