WED-1306

Hello. Using WED Win v.2.20r2
When I'm trying to validate/export scenery pack (!!Unable to render embedded object: File (exporting not to Airport Scenery Gateway) not found.!!), validation fails because I use custom library objects.
It says that:
"The library path path is not part of X-Plane's default installation and cannot be submitted to the global airport database."

I don't need submission to the database. Just exporting.

1. Steps:
Validate/Export Scenery with any custom lib object (I tried with ruscenery, R2, PM and opensceneryx)

Expected:
Successful validation/exporting.

Actual:
Errors for all used object with reason "The library path path is not part of X-Plane's default installation and cannot be submitted to the global airport database."

That's my first experience with WED, so, if that's my dummy fault, sorry)