Hello Barry,
The Devices/Ersatz recognized by the Editor are based on the MIAME associated to the current Project and the ERSATZ file defined in the MIAME, which you can access using the top buttons as illustrated below.
I don't use the same MIAME file for my development area and the Editor, which means that, if I add any device/ersatz in the development area that is needed for the Editor, I must adjust both.
Please, let me know if this solves the issue.