Change 910552 had a related patch set uploaded (by WMDE-Fisch; author: WMDE-Fisch):

[mediawiki/extensions/Cite@master] [POC] Allow reference re-use and editing in other VE dialogs

https://gerrit.wikimedia.org/r/910552

I dug a little bit into this and found:

• When you start VisualEditor with &debug=1 you get a nice tool to see the document model VisualEditor uses. In this model:
  • Templates are a single mwTransclusionBlock node. There is no reference node anywhere.
  • Same for a map where the caption contains a reference. There is a single mwMaps node, but nothing else.
  • For some reason this is different for images. There is a mwBlockImage node, but it contains more nodes, including a mwReference node.
  • The model inside of the image dialog is only the relevant sub-model.
• Still the top-level re-use dialog is somehow able to show most of these references:
  • The reference from the image is always shown.
  • Both references from the map/template show up, but only when they are already re-used outside of the map/template, and only as a number "[2]" with no content.
• One of the references shows up twice. One time without content and name. (Turns out this was because of temporary hacks I made.)
  • In this situation the re-use dialog shows 4 references, but the reference list at the end of the article only 3.
  • All but the reference from the image are marked as "This reference is defined in a template or other generated block, and for now can only be previewed in source mode."
• When I actually re-use one of the bogus references VE creates broken wikitext: <ref />

Which means:

• The proposal in the patch – to use the image's parent document – appears to be correct, but only for images.

To wrap this up: It seems it's quite possible to fix the issue for the images and media and gallery dialogs without much effort.

Change 917903 had a related patch set uploaded (by Thiemo Kreuz (WMDE); author: Thiemo Kreuz (WMDE)):

[mediawiki/extensions/Cite@master] Fix empty previews in reference reuse dialog

https://gerrit.wikimedia.org/r/917903