From 1673c0835349d64b6657517140144493a45c445a Mon Sep 17 00:00:00 2001
From: David Rowe <david@ctrlaltstudio.com>
Date: Fri, 6 Oct 2017 10:42:23 +1300
Subject: [PATCH] Update undo for grouping

---
 scripts/shapes/modules/groups.js  | 10 ++--------
 scripts/shapes/modules/history.js |  8 ++++++--
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/scripts/shapes/modules/groups.js b/scripts/shapes/modules/groups.js
index 223992d646..3153a622ee 100644
--- a/scripts/shapes/modules/groups.js
+++ b/scripts/shapes/modules/groups.js
@@ -143,10 +143,7 @@ Groups = function () {
         selections.splice(1, selections.length - 1);
 
         // Add history entry.
-        History.push(
-            { setProperties: undoData },
-            { setProperties: redoData }
-        );
+        History.push(null, { setProperties: undoData }, { setProperties: redoData });
     }
 
     function ungroup() {
@@ -248,10 +245,7 @@ Groups = function () {
         }
 
         // Add history entry.
-        History.push(
-            { setProperties: undoData },
-            { setProperties: redoData }
-        );
+        History.push(null, { setProperties: undoData }, { setProperties: redoData });
     }
 
     function clear() {
diff --git a/scripts/shapes/modules/history.js b/scripts/shapes/modules/history.js
index 4b84a5699d..3820feaf81 100644
--- a/scripts/shapes/modules/history.js
+++ b/scripts/shapes/modules/history.js
@@ -47,8 +47,9 @@ History = (function () {
         ],
         MAX_HISTORY_ITEMS = 1000,
         undoPosition = -1, // The next history item to undo; the next history item to redo = undoIndex + 1.
-        undoData = [{}, {}],
-        redoData = [{}, {}];
+        undoData = [{}, {}, {}], // Left side, right side, no side.
+        redoData = [{}, {}, {}],
+        NO_SIDE = 2;
 
     function doKick(entityID) {
         var properties,
@@ -81,6 +82,9 @@ History = (function () {
 
     function push(side, undo, redo) {
         // Add a history entry.
+        if (side === null) {
+            side = NO_SIDE;
+        }
         undoData[side] = Object.merge(undoData[side], undo);
         redoData[side] = Object.merge(redoData[side], redo);