Efficient keyboard navigation in the dock panel

[ellisonbg]

One of the hidden benefits of the existing notebook is that users can quickly move between the dashboard and different notebooks (which are just browser tabs) using the default browser shortcuts (command+shift+[]).

JupyterLab will need a similarly efficient set of keyboard shortcuts that allow navigation to different panels/tabs in the dock panel.

There are a number of different ways of doing this - we will have to consider the options.

[fperez]

@jasongrout mentioned in #87:

@fperez - would it be enough to have a button to maximize the current notebook, which maximizes the current tab so that it fills the dock panel or the browser window? What are the use cases for having the URL reflect a single document?

It would certainly be an improvement, but I don't think it's sufficient. I think this question covers two related but separate questions:

1. Notebook-per-browser tab, for keyboard navigation and uncluttered focus.
2. URL for a notebook: this makes it easy to have something to bookmark for often-used notebooks, to reload one open notebook in a different browser (crash, suspected browser bug, etc), or to reload across server sessions (common while developing).

While a maximized notebook would cover (1), it wouldn't really address (2).

[fperez]

Ah, sorry, I had missed #158, which is really where (2) is discussed. Let's continue that there. I think that we should not only provide within-Lab navigation (which we do want), but specifically retain the default browser tab kbd navigation ability (cmd-shift-[]), since that shortcut is one of the most muscle-burned ones in people's workflow (esp. as it's also respected by other tabbed tools, like terminal emulators and some text editors).

@jasongrout's suggestion could work for that...