Actually it did help me, I had to click edit form the camera, not from the Photos app. Pretty obvious now when I think about it.
Agreed, it's obvious after the fact. What about if you 'share' the file from the stock Photos app? A list of programs generally appears. Is one of them the HTC Photo Edit app that could then be selected? I often use the 'share' button to access Snapseed and VSCO editors.
I'd check myself but my phone hasn't arrived yet.
Nope, not a trace of HTC Photo Edit anywhere but in edit in the camera app...