Our office has a fairly extensive library of custom GSM parts. These include cabinets, doors, windows, etc. Historically, we have issued two schedules by building element: (1) a long list of every single element used in the project (e.g. every door) and (2) a "types" schedule which merges similar elements.
In the past, we the schedule "merge items" button has worked perfectly for this second schedule. We include whatever fields are relevant to merge, then if all the fields match in the schedule the objects are merged (and usually listed by Quantity).
But... in v25 ONLY "core" parameter values are compared for merging. For us this results in wildly dissimilar objects being merged---since our custom parameters are all simply now ignored by this function.
I have spent a few days pondering a work around but am now stuck. The only brute force fix would be to stay on v24, but this is not a sustainable approach. All of the values I am able to change (gruesome workarounds to be sure) are still not recognized as "core" values by Archicad. The least bad v25 workaround I can think of would be forcing our PMs to assign "type" values by hand as PROPERTIES. If properly managed this could force a clean types list. But it seems crazy in 2021 that we would need such a fragile workaround.
Please let me know if I am missing some obvious alternative approach to this new issue.
I was having the same issue, and Joskule's answer helped me!
I don't think this is caused by a bug, but a new feature that defaults to this behavior. Since Archicad 25 you have more control over merging values (e.g. you can merge IDs into a single cell, and they will all be listed in the merged cell, separated by commas). This is the only material I found about it:
So, if you list your values as usual, but as an extra step, click this icon next to the header of the field, and change it to only merge identical items, it should work as it used to (at least it did for me).