Selection-menu below should have the Fourth choice (default) selected to begin with.
After that, start entering text into the input box. With one or more characters entered, the selection menu option will start cycling, from First choice for 1 char, Second choice for 2 chars, and so on, wrapping after each 5. This cycling is based on the length of the input value--not the total number of characters entered. So backspace should cycle the selected items backwards.