While a Lan world is availible, hitting edit will crash game.

I was going to log on to my brothers lan server to help with redstone, the server showed up but when i clicked it i could not get on. I will save that for another bug. I went to hit refresh but hit edit instead. The screen changed so that no buttons were avalible to hit and exit and there was no text explaining why the server could not be edited. The game then crashed.