Indexof problem when exporting app

Error generating Yail for screen 5763018682007552_Screen1: : Cannot read property ‘indexOf’ of undefined. Please fix and try packaging again.

“Please fix it”

Next time please use search :mag:

Unfortunately setting Minimum SDK version doesn’t solve such problem.

It is very frustrating that the importer cannot set default values for the properties, which are empty and required.
Moreover the builder shows some cryptic complaints which are too vague for an ordinary user.