Choose a map:

With terrain:
Background: See-through modified OpenFreeMap	- Many vertical artifacts visible
Background: blank | Overlay: line and polygon	- Some Vertical artifacts visible
Background: OSM | Overlay: line and polygon	- No vertical artifacts visible
No terrain:
Background: See-through modified OpenFreeMap	- No vertical artifacts visible
Background: blank | Overlay: line and polygon	- No vertical artifacts visible
Background: OSM | Overlay: line and polygon	- No vertical artifacts visible