Calendar: keyboard support

[bill]

Add keyboard access to Calendar, and to DateTextBox to navigate down to the calendar.

Taken from IBM Design Leadership recommendations.

[nathan]

I can work on this as a part of the work I'm doing for #6416.

The issue I see is with the key bindings. I think that PgUp/PgDn? would make sense for prev/next month. Possibly <SHIFT>PgUp/PgDn? for prev/next year?

The problem is with day changing. We could use Up/Down to move between weeks, and left/right to move between days, - but one issue I see is that Left/Right could cause problems - since you usually want to have them available for moving around within the text box. The flip side of that is you could use Up/Down for prev/next day - but that would not be very easy to move between weeks...

What are thoughts on this?

[nathan]

Also (I don't know where else to put this comment), the patch from #6416 will fix the bug in _DateTimeTextBox where pressing the down arrow will NOT re-show the dialog box (which I noticed was another issue on your spreadsheet). I encountered that bug during the development of the #6416 - but didn't log a separate issue for it.

[nathan]

Reassigning back to becky...some of the work in #6416 might apply to this - but it appears, after speaking with her, that this ticket is meant to track a much larger work than originally I had thought.

[bill]

Assuming we keep focus within the <input> box, like on ComboBox, it seems like left/right arrow should navigate within the calendar (when the drop down is showing), and navigate within the <input> when the drop down is closed. Maybe not ideal but seems like the best compromise?