Hello Hallgrimur,
I'm afraid I've found no way to pass over the File path, the JSON.stringified File Object or anything else (all the snips in my previous post show that).
After the cep showOpenDialog(), each call to a function in the JSX (passing or not passing a value) is broken.
I'm currently trying with the HTML input of type="file", but I've not been able to cook a decent example yet.
Davide