How it should work (and does, if you open the "Basic" dialog):

1. A footnote is used multiple times on the same page.
2. You double-click one of those to edit it.
3. It opens the dialog with a note saying "This reference is used $1 times on this page."

How it is currently working:

1. A footnote is used multiple times on the same page.
2. You double-click one of those to edit it.
3. It opens the citation dialog directly, with no indication that changing the page numbers here is going to screw up the page numbers for all the other copies of that ref on the page.

Proposed solution: Display MediaWiki:Visualeditor-dialog-reference-editing-reused in citation template dialogs.