for saving on a cell which is completely unmodified. One of these
was due to the BPlane implementation, which forces an instance to be
deleted and re-placed on a bounding box recomputation, which should
not, in that case, be considered a modification. Another always runs
DRC on a subcell upon reading rather than relying on any checkplane
entries in the file itself; and the last one marking the timestamp
as modified stemming from an attempt to correct an O(N^2) check to
O(N). All three cases have now been corrected.
Tim Edwards
59bfa6ce86