If I set up a world border, does it apply to all dimensions?
I am tempted to set up a world border in Minecraft but I don't want to be limited in the Nether.
Does the world border effect all dimensions?
If it does can it be configured not to?
World borders do affect the nether. This is stated on the wiki:
In the Nether, the world border's dimensions are the same as the Overworld's.
Unfortunately, there doesn't seem to be a way to configure how world borders behave in different dimensions at this time.
World border in the nether:
I have not been able to test world borders in the end.