Second-to-last cell focused when adding or pasting cells at end of notebook

[JasonWeill]

An issue that happens multiple times per day, but I'm not exactly sure the chain of events that leads to it: the notebook frontend gets confused about what the currently selected cell is, and the order of cells, when I add a new cell to the end (e.g by copy/paste to the end of the notebook, or by hitting shift-enter at the end). I end up with a situation where the final cell is displayed as the penultimate cell, and pressing down causes the selected cell to go to the last cell, and then to the penultimate cell, and vice-versa. I've found I have to refresh the browser to fix this.

I have not been able to reproduce this with the tip-of-main code, with limited testing.

Reported by @jph00 in #7041 (comment).

[JasonWeill]

Closing as a duplicate of jupyterlab/jupyterlab#15610 (thanks @krassowski ), which concerns code that Jupyter Notebook uses. This should be fixed in the tip of main, and should be included in the next releases of Notebook.