"Duplicate items" falsely include a paper and a related conference abstract.
I often add important abstracts of meetings to Zotero as a "Conference Paper". Because they are important, they tend to be published in journals, they often appear with the same title and same authors but as s "Journal Article".
The annoying thing is that "Duplicate items" folder of Zotero include both of them. But when I click one of them in the folder, it says that "Merged items must all be of the same type." I knew it. They're meant to be independent entities.
If they show this error, they can certainly exclude these cases from Duplicate detection. Or if more flexibility is desirable, it should allow us to choose either to consider them as the same entity or not.
The annoying thing is that "Duplicate items" folder of Zotero include both of them. But when I click one of them in the folder, it says that "Merged items must all be of the same type." I knew it. They're meant to be independent entities.
If they show this error, they can certainly exclude these cases from Duplicate detection. Or if more flexibility is desirable, it should allow us to choose either to consider them as the same entity or not.
There is currently nothing you can do about this, just ignore it.
2. You can merge items of different types by first changing the type of one to the same as the other. This is of course best if you change the incorrect one to the correct type first, then merging into the correct one and preserving that information.
This page was useful to see what frustrates other people at the moment.
https://www.zotero.org/support/requested_features#zotero_interface
BTW, I generally love Zotero.