How do I scale/rotate a UV shell independent of other UV shells?

I've been combing the internet with vaguely frantic frustration, because no one seems to have the issue I'm having. I'm using Maya 2016 Trial Edition, which may be confusing the issue (since this course definitely uses Maya LT, and may be using 2015, I dunno). I should hope it isn't, but hey.

Unlike the instructor, I am unable to simply transform, scale and rotate the UVs of the cabinet's body shells without causing the same-edge sections on other shells to warp around it. When I follow the instructor's steps (switch to UV mode -> select one or more vertices of the desired shell -> hit "Select Shell" in the Select menu -> use Maya's general transform tool), several other shells stretch in reaction to any adjustments to the position of the selected shell. I can use the Move UV Shell Tool to position shells without this issue, but there is no equivalent tool for rotation or scale, where the issues remain. To be clear, using the Rotate selected UVs tools cause warping as well.