That's not available to scripting.
Why do you need to get that dropdown selection?
Im glad you think that Harbs… I took a quick look and the AppleScript dictionary said app & doc were valid… Nothing obvious to do this…?
It works the other way around -- you don't 'select' the target for replacement, you act on an object. To change text in a document, you would use
and similar for textFrames, stories, paragraphs, or -- indeed -- any selected text:
app.findTextPreferences = app.changeTextPreferences = null; app.findTextPreferences.findWhat = 'e'; app.changeTextPreferences.changeTo = '!'; app.selection.changeText();
Thats far more obvious now I've seen it… << new glasses by 'Jong'… Prefer your helpers to AppleScript dictionaries…