MultiTerm Script Error: 'onEdit'

Since my last re-install, MultiTerm 2019 won't let me edit some parts of terms (eg. picklists) and keeps throwing this error:

MultiTerm Script Error message "Object doesn't support property or method 'onEdit'"

I'm on Windows 10, my Internet Explorer is fully up-to-date, for all that that's worth, and Active-X is enabled across the board. Java is up-to-date as well, as is MultiTerm.

Anyone have any ideas?