T150418 strips references pasted directed from read mode to VE, but if they are pasted into a third-party editor, it is possible the HTML will be sufficiently mangled that our selector won't work, e.g.
- Copy a reference from read mode
- Paste into LibreOffice writer
- Copy from LO
- Paste into VE
- Observe the linked numbers are preserved (although not the <sup>)