TrEd Extension: gdt (version 1.3)
Provides contexts to annotate GDT files from inside the Tree Editor TrEd at the levels of morphology, syntax, and semantics.
This extension can be installed directly from TrEd, using Setup >> Manage Extensions >> Get New Extensions; just make sure the repositories http://gdt.ilsp.gr/tools/gdt_tred_extensions and http://ufal.mff.cuni.cz/~pajas/tred/extensions/ are enabled in Setup >> Manage Extensions >> Edit Repositories.