Using 4.19 .
Seems trouble started when I started using world composition, trying to tile (to start with) my own terrain plus one added via wc window, to +X via right click. Simple enough.
When I do it with ‘new’ terrains, adding terrain in WC as noted above, everything works AS expected, perfect.
When I do it with my own terrain as noted above, one is higher than the other,NO stitching, though if I sculpt along edge where they do NO line up, the sculpting goes from one edge of one terrain to other edge of the other terrain, making what looks like a sculpted waterfall, of sorts…I hope the visual is adequate if not I can get a screenie.
Short of that, I"m having a new problem,a REALLY odd one…if I chose most objects in scene, there are around 20 or so of them, some Geo meshes turned into single mesh, I can’t SELECT them. WHen I select them IN outliner, they always HIGHLIGHT.
What the heck is going on here ? 
I’ve never had this kind of issue before 
Also can anyone pls let me know what the green line is in IMG below, green ‘dot’ in the middle of it, and when I select it the BP-Sky_sphere is highlighted in outliner but deleting it, doesn’t get rid of the green line, or whatever it is.
