diff --git a/blockly_compressed.js b/blockly_compressed.js
index 28eb0ae8f..0eac58833 100644
--- a/blockly_compressed.js
+++ b/blockly_compressed.js
@@ -1019,9 +1019,9 @@ Blockly.ContextMenu.hide=function(){Blockly.WidgetDiv.hideIfOwner(Blockly.Contex
 // Copyright 2012 Google Inc.  Apache License 2.0
 Blockly.BlockSvg=function(){this.svgGroup_=Blockly.createSvgElement("g",{},null);this.svgPathDark_=Blockly.createSvgElement("path",{"class":"blocklyPathDark",transform:"translate(1, 1)"},this.svgGroup_);this.svgPath_=Blockly.createSvgElement("path",{"class":"blocklyPath"},this.svgGroup_);this.svgPathLight_=Blockly.createSvgElement("path",{"class":"blocklyPathLight"},this.svgGroup_);this.svgPath_.tooltip=this;Blockly.Tooltip.bindMouseEvents(this.svgPath_);this.updateMovable()};
 goog.inherits(Blockly.BlockSvg,Blockly.Block);Blockly.BlockSvg.prototype.height=0;Blockly.BlockSvg.prototype.width=0;Blockly.BlockSvg.INLINE=-1;
-Blockly.BlockSvg.prototype.initSvg=function(){goog.asserts.assert(this.workspace.rendered,"Workspace is headless.");for(var a=0,b;b=this.inputList[a];a++)b.init();this.mutator&&this.mutator.createIcon();this.updateColour();Blockly.readOnly||Blockly.bindEvent_(this.getSvgRoot(),"mousedown",this,this.onMouseDown_);this.workspace.getCanvas().appendChild(this.getSvgRoot());goog.isFunction(this.onchange)&&Blockly.bindEvent_(this.workspace.getCanvas(),"blocklyWorkspaceChange",this,this.onchange)};
-Blockly.BlockSvg.prototype.select=function(){Blockly.selected&&Blockly.selected.unselect();Blockly.selected=this;this.addSelect();Blockly.fireUiEvent(this.workspace.getCanvas(),"blocklySelectChange")};Blockly.BlockSvg.prototype.unselect=function(){Blockly.selected=null;this.removeSelect();Blockly.fireUiEvent(this.workspace.getCanvas(),"blocklySelectChange")};Blockly.BlockSvg.prototype.mutator=null;Blockly.BlockSvg.prototype.comment=null;Blockly.BlockSvg.prototype.warning=null;
-Blockly.BlockSvg.prototype.getIcons=function(){var a=[];this.mutator&&a.push(this.mutator);this.comment&&a.push(this.comment);this.warning&&a.push(this.warning);return a};Blockly.BlockSvg.onMouseUpWrapper_=null;Blockly.BlockSvg.onMouseMoveWrapper_=null;
+Blockly.BlockSvg.prototype.initSvg=function(){goog.asserts.assert(this.workspace.rendered,"Workspace is headless.");for(var a=0,b;b=this.inputList[a];a++)b.init();this.mutator&&this.mutator.createIcon();this.updateColour();Blockly.readOnly||this.eventsInit_||Blockly.bindEvent_(this.getSvgRoot(),"mousedown",this,this.onMouseDown_);this.getSvgRoot().parentNode||this.workspace.getCanvas().appendChild(this.getSvgRoot());goog.isFunction(this.onchange)&&!this.eventsInit_&&Blockly.bindEvent_(this.workspace.getCanvas(),
+"blocklyWorkspaceChange",this,this.onchange);this.eventsInit_=!0};Blockly.BlockSvg.prototype.select=function(){Blockly.selected&&Blockly.selected.unselect();Blockly.selected=this;this.addSelect();Blockly.fireUiEvent(this.workspace.getCanvas(),"blocklySelectChange")};Blockly.BlockSvg.prototype.unselect=function(){Blockly.selected=null;this.removeSelect();Blockly.fireUiEvent(this.workspace.getCanvas(),"blocklySelectChange")};Blockly.BlockSvg.prototype.mutator=null;
+Blockly.BlockSvg.prototype.comment=null;Blockly.BlockSvg.prototype.warning=null;Blockly.BlockSvg.prototype.getIcons=function(){var a=[];this.mutator&&a.push(this.mutator);this.comment&&a.push(this.comment);this.warning&&a.push(this.warning);return a};Blockly.BlockSvg.onMouseUpWrapper_=null;Blockly.BlockSvg.onMouseMoveWrapper_=null;
 Blockly.BlockSvg.terminateDrag_=function(){Blockly.BlockSvg.onMouseUpWrapper_&&(Blockly.unbindEvent_(Blockly.BlockSvg.onMouseUpWrapper_),Blockly.BlockSvg.onMouseUpWrapper_=null);Blockly.BlockSvg.onMouseMoveWrapper_&&(Blockly.unbindEvent_(Blockly.BlockSvg.onMouseMoveWrapper_),Blockly.BlockSvg.onMouseMoveWrapper_=null);var a=Blockly.selected;if(2==Blockly.dragMode_&&a){var b=a.getRelativeToSurfaceXY();a.moveConnections_(b.x-a.startDragX,b.y-a.startDragY);delete a.draggedBubbles_;a.setDragging_(!1);
 a.render();goog.Timer.callOnce(a.bumpNeighbours_,Blockly.BUMP_DELAY,a);Blockly.fireUiEvent(window,"resize");a.workspace.fireChangeEvent()}Blockly.dragMode_=0;Blockly.Css.setCursor(Blockly.Css.Cursor.OPEN)};
 Blockly.BlockSvg.prototype.setParent=function(a){var b=this.getSvgRoot();if(this.parentBlock_&&b){var c=this.getRelativeToSurfaceXY();this.workspace.getCanvas().appendChild(b);b.setAttribute("transform","translate("+c.x+", "+c.y+")")}Blockly.BlockSvg.superClass_.setParent.call(this,a);a&&(c=this.getRelativeToSurfaceXY(),a.getSvgRoot().appendChild(b),a=this.getRelativeToSurfaceXY(),this.moveConnections_(a.x-c.x,a.y-c.y))};
diff --git a/core/block_svg.js b/core/block_svg.js
index 4e05826f7..bf65fcf2d 100644
--- a/core/block_svg.js
+++ b/core/block_svg.js
@@ -81,17 +81,20 @@ Blockly.BlockSvg.prototype.initSvg = function() {
     this.mutator.createIcon();
   }
   this.updateColour();
-  if (!Blockly.readOnly) {
+  if (!Blockly.readOnly && !this.eventsInit_) {
     Blockly.bindEvent_(this.getSvgRoot(), 'mousedown', this,
                        this.onMouseDown_);
   }
-  this.workspace.getCanvas().appendChild(this.getSvgRoot());
+  if (!this.getSvgRoot().parentNode) {
+    this.workspace.getCanvas().appendChild(this.getSvgRoot());
+  }
 
   // Bind an onchange function, if it exists.
-  if (goog.isFunction(this.onchange)) {
+  if (goog.isFunction(this.onchange) && !this.eventsInit_) {
     Blockly.bindEvent_(this.workspace.getCanvas(), 'blocklyWorkspaceChange',
         this, this.onchange);
   }
+  this.eventsInit_ = true;
 };
 
 /**