Is it only me or the merge cell shortcut Shift+M doesn't work anymore?
I tried on different machines with the version 1.0.0.
Thanks.
I think you mean 1.0 of Jupyter ? (Notebook is 4.0, but details, details)
In 4.0 (notebook) you can use Shift-J/K to select multiple cells and Shift-M will merge all the selected cells.

Good to know, I also though it was a bug. @Carreu is there any existing documentation for the notebook UI?
@Carreau, as a user I totally missed this because I didn't realize the shortcut help dialog in the notebook has an hidden scrollbar showing more shortcuts.
Is there a way we can make Shift-M still work like it used to? I don't see why disabling it completely unless the user presses Shift-J/K is a good interface. If there's only one cell selected, why not do what it always used to do (merge below)?
The reason I find it not intuitive is that the 'extend cell selection above/below' hotkey isn't really an option an user would look for if they didn't know what it did beforehand, especially since it's not part of any menu items either.
@mirage007, this has been already proposed: https://github.com/jupyter/notebook/issues/509, please follow up there.
Most helpful comment
I think you mean 1.0 of Jupyter ? (Notebook is 4.0, but details, details)
In 4.0 (notebook) you can use Shift-J/K to select multiple cells and Shift-M will merge all the selected cells.