The ability to have fences not attach to adjasent

I would love it if you could make it so that us players could determine whether or not fences connect to adjacent blocks. There are many examples in which such a feature would be useful. for example: trying to make a chair that is right against a solid table but that chair needs to be higher than a block.

PS the reason this is classified as bug is that for some reason i cannot change it to new feature it's stuck as bug