Mystic confluence did not let me select the counter target spell unless.... mode to target opponent's kicked burst lightning.

1. I have 5 blue lands untapped and mystic confluence in hand
2. opponent casts kicked burst lightning
3. I attempt to cast mystic confluence selecting the first mode once (counter target...) targeting burst lightning, and the third mode twice (draw a card)
4. EXPECTED: I am able to select options described in step 3
5. ACTUAL: 1st mode selection box is greyed out and cannot be selected