You can get the same issue with redo, it seems to be caused by sections that cross uninitialized chunks. It's unable to undo or redo those sections without crashing-QA Testing-
{F6922}
```[2016-03-27 16:47:16] java.lang.NullPointerException: Exception: REQUESTED TYPE 0 IS NULL
[2016-03-27 16:47:16] at org.schema.game.common.data.element.ElementKeyMap.getInfo(SourceFile:596)The nullpointer is fixed, I do however notice that in some cases an undo will not be complete.
[2016-03-27 16:47:16] at obfuscated.cR.a(SourceFile:45)
[2016-03-27 16:47:16] at org.schema.game.common.controller.EditableSendableSegmentController.redo(SourceFile:2332)
[2016-03-27 16:47:16] at obfuscated.ds.h(SourceFile:1815)There is no item loss or duplication, it just doesn't undo the entire action and it seems to be chunk related.
{F7025}
An easy example to reproduce is:
[2016-03-27 16:47:16] at obfuscated.da.f(SourceFile:163)# place down a 10 x 10 x 10 cube of something right on a shipcore
[2016-03-27 16:47:16] at obfuscated.oh.callback(SourceFile:849# remove a 8 x 10 x 10 box at the side where the it crosses over into another chunk (just remove a part furthest away from the ship core)
[2016-03-27 16:47:16] at org.schema.schine.network.client.GUICallbackController.execute(SourceFile:40)# undo twice, redo twice
[2016-03-27 16:47:16] at obfuscated.C.updateStateInput(SourceFile:1365)
[2016-03-27 16:47:16] at obfuscated.avy.a(SourceFile:1167)# undo once
You should see something like that picture instead.
[2016-03-27 16:47:16] at obfuscated.C.h(SourceFile:2866)
[2016-03-27 16:47:16] at obfuscated.QF.run(SourceFile:92)Same can be done with redo.
This sort of thing used to crash you, which doesn't happen anymore but you get a broken undo/redo.
[2016-03-27 16:47:16] at java.lang.Thread.run(Unknown Source)```