[css3-regions] Margins when breaking an auto-height region

Hi Alan,

I was wondering what happens with the margins when an auto-height region is ended by a forced break. The CSS Fragmentation specification states [1] that the margins before the break are truncated and the margins after the break are preserved.
With auto-height regions the break point is not pre-determined and can change based on how we chose to treat margins.

In my opinion the expected behaviour would be:
1. prevent the margin collapsing around the break point
2. place the before-break margin in the auto-height region
3. make the break and end the auto-height region
4. place the after-break margin in the next region
5. continue laying out the next box

Thoughts?

Thanks,
Andrei.

[1] http://dev.w3.org/csswg/css3-break/#break-margins