Due to fixing issue 84690, the following issue has arisen:

- Create a new schema file.
- Clone the window and put the two editors side-by-side.
- Switch the first editor to Source view (the clone is in Schema view).
- Add a new element in the source editor (using copy/paste is fine).

Observe that the element does not appear in the Schema view of the cloned
editor. Prior to fixing issue 84690 this used to work.

The problem is that the editor, cloned or otherwise, can only be listening to a
single undoable edit source at a given time (in order to fix issue 84690). In
this case, the editor showing the Source view is the active TopComponent, so the
clone showing the model view is not listening to the undoable edit source. But
this should not matter as it is not the undoable edits that the Schema view is
listening to, so perhaps this is a model auto-sync issue. Needs more investigation.