At 640×360 the mock's first shop card completes a merge; its detail opens in
the left slot and moves to the right one 20-40 ms later because the elite's
lit board tile lies under the left slot (screens/game.js dSide, DESIGN
§20.11). The check caught the left card only sometimes and then measured the
corner buttons against the right one. It now taps a card without a merge and
asserts the card stays left.