I've tried to browse the apps but it seems like there some bug in the extension. Is that the cause of the "grey area"?
I am also facing the same problem. Would you please share the app on which you made it work? I can use it as a reference.
Even I am using coordinates as lat,long format and for region dimension I am using Country's name.
I would greatly appreciate if you can provide something or point me to a direction where I can find something useful.