When attempting to auto-complete a reference field value in a filter, the input field is covered with the suggestions list. When only one result is returned, a one-item list appears *above* the text field, but you need to use the *down* arrow to select it using the keyboard.
Steps to Reproduce
Navigate to Incident > Open (or fix targets or stories).
Open the filter builder and add a new AND clause.
Choose Configuration Item (Problem on HI, or Target Branch for fix target or story).
Tab over to the text area and type a single character.
Note that suggestions appear starting above the text area and continuing down over the top of it
Although the suggested text covers the input field, the characters are input and the filter is built as desired
Related Problem: PRB721465