Allow cancelling of a planned cell's execution

[arjunv]

I'm typing up this issue while waiting for cell 4 to complete execution. I'd say I still have a few more hours to wait on this. Before I can call it a day and go home, I need cells 6 and 7 to be executed as well. So I ran them and packed up my bags.

As fate would have it, there's a teeny bug in the tiny code that runs on cell 6. And now, jupyter doesn't allow me to cancel a planned cells execution or re-order the cell execution queue.

So now, I wait and think about you. You're facing this as well, huh? Sucks to be here, I know.

[kevin-bates]

So now, I wait and think about you. You're facing this as well, huh? Sucks to be here, I know.

Hi @arjunv - we appreciate the thoughts and, yes, do care about our users. The community's maintainers do their very best to keep up with issues and features, in addition to their own efforts. This issue has come up several times and I've included references to where those discussions have taken place. There may be others as well.

Here's one of the earlier ones. https://github.com/jupyter/notebook/issues/2340

Since new server features won't happen in Notebook, this next link, relative to JupyterLab, will likely include Jupyter Server (and jupyter_client) for any server-side changes.
https://github.com/jupyterlab/jupyterlab/issues/7825

[jasongrout]

I put some more ideas about how we might expose the execution queue to the user at https://github.com/jupyterlab/jupyterlab/issues/7825#issuecomment-1033901163