Alright, so my brother made a world and opened it to LAN. We receive internet from the same wireless router, so we should be able to connect. But I noticed a strange IP under the LAN world name: it was something like
192.168.2.5:0.0.0.0:[can't remember this number, i guess its the port it mentions when opening to LAN] Anyways, just out of curiosity I pressed Edit and it crashed.

What I expected to happen was...:
Nothing since it's a LAN world from my brother and I shouldn't be able to edit it.

What actually happened was...:
Game crashed.

Steps to Reproduce:
This bug has never happened to me before thus it is very unprobable to happen twice, in any case a second computer hosting a LAN world is required.
1. Open Minecraft and go to Multiplayer
2. LAN world should appear with strange IP.
3. Click Edit and watch it crash.
I guess Edit is not intended to be used on LAN worlds so fixing it won't be much of a problem.