This still not gives the "footnote and entry" are on same page invariant for blocks, but at least we do not get random extraneous page breaks anymore.
Relevant issues: #1275, #1433
Fixes#1216 both by hardening the rounded rectangle against negative size and by ensuring that the negative size doesn't occur in the first place for this case.
Having a table span multiple pages can cause an alignment bug in the
table itself. If the first region in a cell in a grid row is empty, all
other cells in this row will skip the first region. A misalignment bug
can occur, since the calculation of all region sizes happen before the
skip. The overall size allocated for the content of a cell with multiple
regions and content in the first region thus is too little.
Fixes#963
