This issue is kind of difficult to explain, and pictures don't exactly help. I placed one of the larger railings in the upper right portion of the Biodome: You can actually see it in this video for the first minute or so. If I scroll to the left, the decoration gets "stuck" on the edge of the screen and moves across. However, it remains in its original position, and seems to run into a wall at its left-most corner where it becomes invisible.
Have I confused you enough? Like I said, I don't know quite how to describe it! I've taken a few pictures that I can gladly post, if they'll help. I haven't fully tested this issue to see if it's only the one railing that's affected, although it appears to be so. I also confirmed that it isn't the options panels that create the issue: When they're fully opened, the decoration still only reacts to the edge of the screen.
This might be more of a tweak than an annoyance, so feel free to downgrade it!