Often when there are entities at a long distance from the origin weird camera behaviour occurs.
If you go to camera>parallel projection. The background does not display as you would expect when orbiting.
If you set the camera>perspective. The background displays in a normal manner when you orbit the model.
In the image below there are 13 pieces of text in the model, however there are only 10 visible in the model space. That probably means there are 3 pieces of text or leaders floating around somewhere causing the camera to behave strangely.
I tried to find and delete the 3 pieces, to no avail. What I then did were selected all the model and copy/pasted it into a new file, with the urban planning template you mention. Hoping I wouldn’t take the 3 stray pieces with it.
The shot below shows now only 10 pieces of text in the model statistics and 1 less edge that I think must have been floating too. The model appears to be behaving in a more normal way.
This is the new file G12 IanT.skp (100.6 KB)