diff --git a/core/inject.js b/core/inject.js
index 5ee706d15..df7b48179 100644
--- a/core/inject.js
+++ b/core/inject.js
@@ -224,7 +224,7 @@ Blockly.createMainWorkspace_ = function(svg, options, blockDragSurface,
   Blockly.mainWorkspace = mainWorkspace;
 
   if (!options.readOnly && !options.hasScrollbars) {
-    var workspaceChanged = function() {
+    var workspaceChanged = function(e) {
       if (!mainWorkspace.isDragging()) {
         var metrics = mainWorkspace.getMetrics();
         var edgeLeft = metrics.viewLeft + metrics.absoluteLeft;
@@ -239,6 +239,12 @@ Blockly.createMainWorkspace_ = function(svg, options, blockDragSurface,
           // One or more blocks may be out of bounds.  Bump them back in.
           var MARGIN = 25;
           var blocks = mainWorkspace.getTopBlocks(false);
+          var oldGroup = null;
+          if (e) {
+            oldGroup = Blockly.Events.getGroup();
+            Blockly.Events.setGroup(e.group);
+          }
+          var movedBlocks = false;
           for (var b = 0, block; block = blocks[b]; b++) {
             var blockXY = block.getRelativeToSurfaceXY();
             var blockHW = block.getHeightWidth();
@@ -246,26 +252,37 @@ Blockly.createMainWorkspace_ = function(svg, options, blockDragSurface,
             var overflowTop = edgeTop + MARGIN - blockHW.height - blockXY.y;
             if (overflowTop > 0) {
               block.moveBy(0, overflowTop);
+              movedBlocks = true;
             }
             // Bump any block that's below the bottom back inside.
             var overflowBottom =
                 edgeTop + metrics.viewHeight - MARGIN - blockXY.y;
             if (overflowBottom < 0) {
               block.moveBy(0, overflowBottom);
+              movedBlocks = true;
             }
             // Bump any block that's off the left back inside.
             var overflowLeft = MARGIN + edgeLeft -
                 blockXY.x - (options.RTL ? 0 : blockHW.width);
             if (overflowLeft > 0) {
               block.moveBy(overflowLeft, 0);
+              movedBlocks = true;
             }
             // Bump any block that's off the right back inside.
             var overflowRight = edgeLeft + metrics.viewWidth - MARGIN -
                 blockXY.x + (options.RTL ? blockHW.width : 0);
             if (overflowRight < 0) {
               block.moveBy(overflowRight, 0);
+              movedBlocks = true;
             }
           }
+          if (e) {
+            if (!e.group && movedBlocks) {
+              console.log('WARNING: Moved blocks in bounds but there was no event group.'
+                        + ' This may break undo.');
+            }
+            Blockly.Events.setGroup(oldGroup);
+          }
         }
       }
     };