This one is indeed tricky. I found that when you get to the last little "gate", if you will, if you don't get the bubble you need, you can actually angle it to the upper right ice formation by aiming *just* outside of the right of the gate. For that reason, try to pop the last gate magnifying glass with the color that is not in the right corner, in case you get a wrong one, you can toss it to the right.