Comment 18 for bug 1760097

I just knocked up a version of ZONE_FILLER::Fill() which rebuilds all the poly lists (but doesn't set them into the zones), and then checks their MD5 hashes against the existing MD5 hashes.

We could get rid of the checkbox and call this routine; if the hash-compares fail then we could ask the user if they wanted to re-fill or not.

Worst case it would re-fill every zone twice. So I guess there's also the option of keeping the checkbox and only calling the new routine when it's unchecked.

(Of course the option of deciding this is too risky for 5.0 is also on the table.)