I know this is really really late. You may have solved this by now.
That blue and white tile you can see, looks like your water plane and skydome.
If they are within your persistent level, then they should™ be hidden in the world composition panel.
However, if they are contained within another level (an atmosphere level or something) then they wont be hidden in the world compositor.
You will need to set the atmosphere level as the active level, then open the “Level Details” panel and tick “Hide in Tile View”.
I hope this helps you and any others that stumble upon this.
EDIT: It looks like the second image you are showing has two copies of the skydome and water.