I have installed proto and started using it. Lots of potential there!
I am; however, experiencing inconsistencies with editing of the text elements. Double taps don't always work and it seems that the paragraph text element is not editable (is that true?).
I would suggest that editable elements receive a link in the context menu (which now only includes delete and duplicate). This would be a much more intuitive way to edit the items.
Great app and keep it up.
You are correct, Text headings are editable but not Paragraph Text. Two quick taps in rapid succession on a Test heading element should allow you to edit the actual text. I like your suggestion for a having an option for editing the text in the context menu, great suggestion. I created an idea for it here.