errors from the area checked must use the same area as is used
by the interaction checker to recompute errors. In earlier code,
both these areas were much larger than necessary. In the last
code update, the area to make revised checks was reduced, but
the area cleared of errors was not, resulting in errors that
would disappear from the layout as paint changes were made, until
a full "drc check" was run again. This code commit makes the
areas the same again so that no errors are lost.