Im trying to explain when this occurs: This is happening to me if i am trying to put all Items in my Inventory at once into a chest. I do this, this way : I am putting an item and shift double click with right click the other at once. Always if im tryed to repredouce this bug, ive got an full inventory with stacks of an cartain item for example Nehter_Quartz. After shift clicking with right click on an item stack i am getting the death animation, and do not die, but i cant write or performe any action except moving. After a recconect i getting the death-screen. If i respawn and goto to pleace where this bug happened to me, all the items ive tryed to move in the chest are lost/missing except the one ive got grapped (the on ive bind to the occurs). There are other situations as well when this bug occurs but these all are have something to do with the new key combinations. For example this also somethines happening by crafting. I am not sure if this is a bug or just cause by something else, but it would be great to get more information about this, to solve this problem. These is the error-message: (if just replaced my ip with some '*') 07:20:10 [WARNING] Failed to handle packet for Hawk/***.***.***.*: java.lang.IndexOutOfBoundsException: Index: 68, Size: 45 java.lang.IndexOutOfBoundsException: Index: 68, Size: 45 at java.util.ArrayList.rangeCheck(Unknown Source) at java.util.ArrayList.get(Unknown Source) at net.minecraft.server.v1_5_R2.Container.clickItem(Container.java:209) at net.minecraft.server.v1_5_R2.PlayerConnection.a(PlayerConnection.java:1201) at net.minecraft.server.v1_5_R2.Packet102WindowClick.handle(SourceFile:31) at org.spigotmc.netty.NettyNetworkManager.b(NettyNetworkManager.java:174) at net.minecraft.server.v1_5_R2.PlayerConnection.d(PlayerConnection.java:113) at net.minecraft.server.v1_5_R2.ServerConnection.b(SourceFile:35) at org.spigotmc.netty.NettyServerConnection.b(NettyServerConnection.java:66) at net.minecraft.server.v1_5_R2.MinecraftServer.r(MinecraftServer.java:582) at net.minecraft.server.v1_5_R2.DedicatedServer.r(DedicatedServer.java:229) at net.minecraft.server.v1_5_R2.MinecraftServer.q(MinecraftServer.java:471) at net.minecraft.server.v1_5_R2.MinecraftServer.run(MinecraftServer.java:403) at net.minecraft.server.v1_5_R2.ThreadServerApplication.run(SourceFile:573) 07:20:12 [INFO] Hawk[/***.***.***.*:*****] logged in with entity id 3960 at ([City] 271.3656642766241, 66.0, -9.579990523554404) /edit found the bad guy. Its a plugin named Anti-Cheat.