Multiplayer crash

Put the summary of the bug you're having here

What I expected to happen was...:
I was trying to connect to a LAN world, and I clicked the "edit" button.

What actually happened was...:
the game crashed with this text:

---- Minecraft Crash Report ----
// Ooh. Shiny.

Time: 6/13/13 7:18 PM
Description: Updating screen events

java.lang.IndexOutOfBoundsException: Index: 6, Size: 6
	at java.util.ArrayList.rangeCheck(Unknown Source)
	at java.util.ArrayList.get(Unknown Source)
	at bcr.a(SourceFile:54)
	at avc.a(SourceFile:170)
	at avt.a(SourceFile:71)
	at avt.d(SourceFile:125)
	at avt.m(SourceFile:109)
	at atl.k(SourceFile:1152)
	at atl.T(SourceFile:654)
	at atl.d(SourceFile:610)
	at net.minecraft.client.main.Main.main(SourceFile:85)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at java.util.ArrayList.rangeCheck(Unknown Source)
	at java.util.ArrayList.get(Unknown Source)
	at bcr.a(SourceFile:54)
	at avc.a(SourceFile:170)
	at avt.a(SourceFile:71)
	at avt.d(SourceFile:125)
	at avt.m(SourceFile:109)

-- Affected screen --
Details:
	Screen name: avc
Stacktrace:
	at atl.k(SourceFile:1152)
	at atl.T(SourceFile:654)
	at atl.d(SourceFile:610)
	at net.minecraft.client.main.Main.main(SourceFile:85)

-- System Details --
Details:
	Minecraft Version: 13w24a
	Operating System: Windows 8 (x86) version 6.2
	Java Version: 1.7.0_17, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 146797920 bytes (139 MB) / 255033344 bytes (243 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 1, tallocated: 63
	Launched Version: 13w24a
	LWJGL: 2.9.0
	OpenGL: Intel(R) HD Graphics 4000 GL version 4.0.0 - Build 9.17.10.2828, Intel
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Texture Pack: Default
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: ~~ERROR~~ NullPointerException: null

Steps to Reproduce:
1. Go to the mutiplayer menu
2. Start a LAN world on a different computer
3. On the first computer, join the LAN game, but cancel before getting into the game
4. Click 'edit' or 'delete'