Given a search box that has a menu which opens after the user begins to type listing results in two columns, plus a "view more results" button and a "close" button, what are the correct keys for navigating this structure with the keyboard?
See this image for a visual representation: http://postimg.org/image/4bd8264zd/
My thoughts so far:
Using up/down arrows while the text box stays focused would work just fine for going up and down the list, but
The left/right arrows, which seem intuitive for moving between the left and right column, already have the job of moving the carrot in the text field. The user might mean to move the carrot, or move between columns but never both at once.
It might be possible to skip left/right for column selection and make the down arrow wrap to the next column when you get to the last result of the previous column.
The tab key makes the most sense for getting focus from the text box to the "close" and "more" buttons, but the results are in between. What effect, if any, does tab have on the result list?