Editing existing TheoryTabs does not allow adding new voices,
Child of Are (Intro).
Editing with the “Edit” option on its tab entry does not allow polyphony.
Copying it into HP2 allows polyphony:
Diva’s Device (Intro) does not allow polyphony:
However, the Pre-Chorus tab, submitted 2016-01-27 and last edited 2020-04-22, does not allow polyphony, but yet has it, following my April 22nd edit. I can still change what voice to pick, as well as edit the voices normally:
Submitting brand new tabs with polyphony works as intended (the submitted tab has polyphony). Only editing tabs with the “Edit” dropdown option does not allow for new polyphony.