Currently the TheoryTab Contributor Guide reads as follows:
Exceptions to these guidelines should be made when the intent of the chord progression suggests otherwise, and contributors should use discretion to identify which spelling is more appropriate. In the following example from C Major, the E7 chord is functioning as a deceptive cadence resolving to F as opposed to Am, and so here the spelling of E7 as V7/vi is appropriate:
This is at the end of a section about borrowed vs applied chord spellings, but the chord in question has no borrowed spelling (in Hookpad), so it really doesn’t illustrate the point of breaking from the rules. Sure, it’s a better spelling than IV7/viidim, but that’s neither here nor there.
The borrowed spelling of E7 in C major is III7, but it is a supermodal chord, meaning it’s not available from parallel modes. I agree with the contributor guide that V7/vi is appropriate due to the deceptive resolution to F and I think the example is totally fine. It perfectly showcases how labeling a chord as an applied dominant can be appropriate eventhough it doesn’t resolve as expected.
I mean that it doesn’t work as an example for Hookpad, because you can’t write III7 except in applied notation. I edited the OP accordingly.
Either type III7 into the search bar or change the key to relative phrygian and borrow I7 from myxolydian.
This is a paid feature, and I would hope Hookpad does not expect their free contributors to pay to adhere to a style guide.
This workaround technically works but it’s not mentioned in the contributor guide so I wouldn’t assume Hookpad expects contributors to know it.
