I've made some significant progress with this, but now I'm getting down to the parts where I have obsolete properties entangled with similar live properties in method signatures and code blocks. I've managed to eliminate three of the four obsolete properties from MdhRecordList: $isEmbedded, $parentId, and $parentIdField. These are hardly used at all by other classes, so eliminating them was simply a local issue, with a few exceptions.

The remaining property is $parentSuffix, and this is problematic because it's passed to any child MdhRecord objects, and referenced throughout the code of both classes, although I don't believe it's actually used at all any more. This is what I believe to be the case, after my first reading of the code and comments:

• I don't believe any of the current code makes use of the MdhRecordList::parentSuffix property at all; it's set to an empty string and never changed.
• However, it is invoked in many locations in the code. Where it occurs in direct functions writing out XHTML, I believe it could simply be eliminated.
• It is also passed to any child MdhRecord objects, where it is assigned to MdhRecord::parentSuffix. Inside the MdhRecord class this is frequently invoked. Generally it is chained together with MdhRecord::localSuffix, a property which is used, and is essential, to ensure that individual forms and form elements have unique id attributes.
• The Adaptive Fields library adaptive_fields.php uses a property with the same name, but I don't believe there's any direct connection between the two.
• When MdhRecord uses a suffix, it's usually done by calling its getSuffix() method, which chains together parentSuffix and localSuffix. In current usage, since the parentSuffix is always set to an empty string, I believe only the localSuffix is ever written out.

Given this, I think this might be a suitably cautious approach to eliminating this complication:

• Start with MdhRecordList, and ensure that nothing can set the value of $parentSuffix to anything except an empty string. Test thoroughly.
• Next, move to MdhRecord, and ensure that nothing can set its $parentSuffix to anything but an empty string. Test again.
• If all is well, eliminate all uses of $parentSuffix from MdhRecordList and test again. This will leave the class making calls to MdhRecord methods where it supplies an empty string in place of its $parentSuffix.
• Identify those methods in MdhRecord, and refactor them so that they don't require that parameter; then remove it from all calls to the methods. Test very thoroughly.
• Remove all remaining code from MdhRecordList which references $parentSuffix, and test again.
• Remove all code referencing $parentSuffix from MdhRecord, and test again.
• Examine gui.js. This has functions which look for the parent suffix and use it (although I believe it's always an empty string) to build ids for form elements and querystring parameters. Remove all references to it, and test again.
• Look at get_rec.php and save_rec.php to see if mentions of suffixes and ids therecan now be simplified.
• Test test test test...