Morning —
I don’t seem to be able to place scenery in the bottom row of the screen to the right of centre. Here’s a picture:

I’ve put two trees in to illustrate the problem – I just can’t put anything in that circled area. I’m working around it fine – I can just move everything to the left, although of course that does leave the far right-hand end still unusable.
The area here is a medium-sized outdoor area. I’m not sure if it’s restricted to that or not.