No more cell collapse

[domloong]

In the latest datalab version, it appears the cell collapse feature has been taken away. Is it possible to bring this feature back? I found it quite useful for keeping notebooks clean and not getting too long.

[ojarjur]

@domloong That feature is still there, but there seems to be some sort of race condition bug that gets triggered the first time you open the UI.

Try refreshing the notebook page and see if the per-cell menu shows up again.

I've been able to reproduce the issue as follows:

1. Open a notebook
2. Open the Chrome developer tools, switch to the network tab, and then select the "Disable cache" option.
3. Refresh the page

Following those steps, the per-cell menu never shows up. However, if I re-enable the cache and refresh the page, then the per-cell menu shows up again.

That leads me to suspect that there may be a race condition that is triggered by how quickly the various static resources are downloaded.

[ojarjur]

Forwarding to @yebrahim, since he knows that code the best.

[yebrahim]

As far as I can see, this regression is caused by the migration to notebook==5.0.0, which does away with (frustratingly) some of the Javascript events. We use the notebook load event to add the cell mini toolbar. I'll look into restoring this functionality.

[melom13]

This issue is also affecting an SPL Analyzing Natality Data Using Datalab and BigQuery, GSP012 - I was running in Google Chrome. It would be great to get this fix released.