The suggestion dropdown opens downward by default. When there is no room for
it below the input in the visible viewport — clipped by the window
edge, a soft keyboard, or pinch-zoom — it flips up and opens above the
input instead. Two widgets sit side by side to show that each dropdown
anchors to its own input (anchor-scope prevents
cross-binding).
Scroll so the fields are near the bottom of the window, then focus each and type. On a phone, the dropdown opens above the soft keyboard.