Here's what I want to do:
I have footage witch I want to divide into several different squares at the same time (think "24"), while also cropping the footage so that I can show certain parts of the original material. All this I can do with the "crop" and "scale" functions under "motion". However, I would also like to zoom in, within one of these frames, during the video. If I use scale for this, the whole frame gets bigger. That's not what I want.
I've circumvented the problem by creating a white square, placed it on a video track higher in the hierarchy than the one I want to manipulate, then using color key to let the footage shine through the white parts. However, this isn't especially confortable to use, especially since I haven't found any good way to feather the edges of the box.