I have clipped (to a ellipse shape) and enlarged a portion of a map to show detail, by using a new data frame layer. All looks well on the layout view, but when exported (to pdf, but I note it is the same for any export) the clip is there but surrounded by the remainder of the frame obscuring the layer below. I realise you can change this frame background colour - but is there any way of making it transparent? or have I gone about the whole exercise the wrong way?
I tried to do it using a clip to a shape and it always looked good on screen, but would not plot. I recall a forum post that came to this conclusion with ESRI staff explaining that it would not work.
If you find out differently, certainly post your finding!