Once bug 663778 is fixed, it would be nice to display the highlighter a bit differently for css transformed elements. The idea is to draw something like this: http://codepen.io/captainbrosset/full/lHpnK (I'll attach a screenshot too). Which would let you see where the original box was supposed to be, and where the transformed box is now, possibly with 4 arrows, one for each corner.

A couple of extra notes: When an image is transformed only the border and content are moved. The margin, padding, border and content still take the same space on the page. It would make sense to show the box model as normal but with the border and content transformed in this way.

I wonder why this bug is still around, the css-transform-highlighter has been done for a long time. Closing this now.