jQuery mobile selectmenu not accessible by keyboard entry

[clehnert-psl]

I'm using jQuery Mobile 1.4.5 and allowing it to style the select menus (not using native selects). I can access the menus using the keyboard by typing enter to open and the arrow keys to move through the options, but I cannot select an option by typing a letter or combination of letters as usual for a native selectmenu. Because of this (from the jQm site), I'd expect full keyboard functionality:

The select menu is ARIA-enabled and keyboard accessible on the desktop
as well.

Here is a closed issue that I thought might address this, but even upgrading to 1.5.0-pre, there is no keyboard selection by letter.

Is this a bug, or is this just not a feature of jQm?

Is there any way I can extend it's functionality to allow word selection by keyboard letter?

JSBin example here