This may be a wishlist item!

For the moment you can do it - as you say - with all the entries of a particular glossary by using the Workshop in the Importer.

To change a short form in the Add Glossary Entry window, the fastest would be to do Shift Home and overwrite the 2 letters by 4 letters.

I will add the "attribution of different default short forms" to the wishlist and see what we can do.

Marianne