Wanting perfection, (a downfall of having CDO, which is OCD, but in the correct order ), I run DDRs and then put them through Goya's BaseElements (BE) to test for any issues that may give rise to problems down the road.
Especially YUCKY (an official word meaning "not wanted in a solution delivered to a client"), are elements which had a script attached, perhaps with a parameter and the script has gone missing. If the client accidentally clicked on the offending item, it would cause the dreaded "This script cannot be found or has been deleted." dialog. Since many clients are not FileMaker developers, they worry when they see this message, thinking they may have done something wrong or even worse - their developer did something wrong!
Recently a BE scan of an almost perfect solution discovered such an element. Now BE is a wonderful tool which I highly recommend, but, it just can't tell you everything. Although it reported the location on the layout where the offending element resided, my eyes just could not see it. Try as I might, there was nothing to be found at 2, 369, 22, 389.
Using a technique of halves, and several more DDRs and imports into BE, I discovered the element, although I was never able to see it. But behavior change in 12 is part of the situation, so I thought I'd pass on this information in case some of you encounter something similar.
The element in question was a portal which was positioned at 675, 621, 1008, 701. At some point in the build process, this portal had held a 20 x 20 button which was attached to a script that was deleted. A different button, this time 16 x 16 had a new script attached to it. BUT, the portal – since portals in 12 magnetically hold onto items placed inside their boundaries – still remembered the original element/button. It is not clear why the portal thought the element was 2 pt from the top of the page, but it did.
The process of halves (dup the layout, remove half the items, run new DDR just for layouts, pull into BE and see if problem still exists), narrowed down the issue to the portal itself. When it was the only element left on the layout, even though the 20 x 20 button could not be seen, some fragment of it still existed in the portal's memory – if there is such a thing.
In any event, creating a new portal from scratch and then moving the elements that should remain onto it, and finally deleting the BAD portal solved the issue. And best of all, removed all ERRORs from the solution in question, at least as far as BE is concerned.
Once again... perfection!