It seems that if you try to realign a wire fence from horizontal to vertical, it works fine, but once it’s in vertical alignment, you just get You cannot build here! if you try to realign it. (Newly built wire fences are in vertical alignment from the start, but I managed to realign an existing fence. (To my great dismay.))
Wire gates, not sure if I’m missing something about how they work, but I can’t seem to build them anywhere at all. Not on pavement, not on dirt, not free standing nor next to a wire fence.