I can seem to edit multiple landscapes at once with world composition enabled, there will be seems at the edges of the levels bounds as shown here -> http://i.imgur.com/eAkKw2o.jpg?1
I have two reasons for needing World Composition, 1st is to have a world overview of the many types of assets I’ve and hide them at will and 2nd I am wanting an ambitious map scale to have practice at nearly every element that goes into developing a game from scratch.
This is my first real game engine I’ve actually used but I am decent enough with various aspects of the engine
Looks like you have created 4 separate Landscape actors. Seamless painting is only possible between landscape actor and its ‘proxies’. Proxies can be created by Landscape editor ‘Move To Level’ tool or by importing tiled heightmap. Also you can right click on a Landscape actor tile inside world composition window and choose “Add adjacent landscape” from context menu. This will add a new sub-level with a landscape proxy of the same size as source landscape actor.