So Google deprecated their GUI builder.. now I'm stuck with a GUI I cannot modify.
They allow you to export the gui as a .txt file containing a json with all the nodes..
Question is - what do I do with it? Is it still useable or am I doomed? :)
All you can do is use that json to manually reconstruct it on uiApp. There is no automated way. But google advises to use htmlService so go the extra effort and go html.