diff --git a/blockly_compressed.js b/blockly_compressed.js
index ddcb076af..acb22ceaa 100644
--- a/blockly_compressed.js
+++ b/blockly_compressed.js
@@ -992,7 +992,7 @@ Blockly.WorkspaceSvg=function(a){Blockly.WorkspaceSvg.superClass_.constructor.ca
 Blockly.WorkspaceSvg.prototype.trashcan=null;Blockly.WorkspaceSvg.prototype.scrollbar=null;
 Blockly.WorkspaceSvg.prototype.createDom=function(a){this.svgGroup_=Blockly.createSvgElement("g",{},null);a&&(this.svgBackground_=Blockly.createSvgElement("rect",{height:"100%",width:"100%","class":a},this.svgGroup_),"blocklyMainBackground"==a&&(this.svgBackground_.style.fill="url(#"+this.options.gridPattern.id+")"));this.svgBlockCanvas_=Blockly.createSvgElement("g",{},this.svgGroup_);this.svgBubbleCanvas_=Blockly.createSvgElement("g",{},this.svgGroup_);this.options.hasTrashcan&&this.addTrashcan_();
 Blockly.bindEvent_(this.svgGroup_,"mousedown",this,this.onMouseDown_);this.options.hasCategories?this.toolbox_=new Blockly.Toolbox(this):this.options.languageTree&&this.addFlyout_();this.fireChangeEvent();return this.svgGroup_};
-Blockly.WorkspaceSvg.prototype.dispose=function(){this.rendered=!1;Blockly.WorkspaceSvg.superClass_.dispose.call(this);this.svgGroup_&&(goog.dom.removeNode(this.svgGroup_),this.svgGroup_=null);this.svgBubbleCanvas_=this.svgBlockCanvas_=null;this.flyout_&&(this.flyout_.dispose(),this.flyout_=null);this.trashcan&&(this.trashcan.dispose(),this.trashcan=null)};
+Blockly.WorkspaceSvg.prototype.dispose=function(){this.rendered=!1;Blockly.WorkspaceSvg.superClass_.dispose.call(this);this.svgGroup_&&(goog.dom.removeNode(this.svgGroup_),this.svgGroup_=null);this.svgBubbleCanvas_=this.svgBlockCanvas_=null;this.flyout_&&(this.flyout_.dispose(),this.flyout_=null);this.trashcan&&(this.trashcan.dispose(),this.trashcan=null);this.options.parentWorkspace||goog.dom.removeNode(this.options.svg)};
 Blockly.WorkspaceSvg.prototype.addTrashcan_=function(){this.trashcan=new Blockly.Trashcan(this);var a=this.trashcan.createDom();this.svgGroup_.insertBefore(a,this.svgBlockCanvas_);this.trashcan.init()};Blockly.WorkspaceSvg.prototype.addFlyout_=function(){this.flyout_=new Blockly.Flyout({parentWorkspace:this,RTL:this.RTL});this.flyout_.autoClose=!1;var a=this.flyout_.createDom();this.svgGroup_.insertBefore(a,this.svgBlockCanvas_)};
 Blockly.WorkspaceSvg.prototype.resize=function(){this.toolbox_&&this.toolbox_.position();this.flyout_&&this.flyout_.position();this.trashcan&&this.trashcan.position();this.scrollbar&&this.scrollbar.resize()};Blockly.WorkspaceSvg.prototype.getCanvas=function(){return this.svgBlockCanvas_};Blockly.WorkspaceSvg.prototype.getBubbleCanvas=function(){return this.svgBubbleCanvas_};
 Blockly.WorkspaceSvg.prototype.translate=function(a,b){var c="translate("+a+","+b+")";this.svgBlockCanvas_.setAttribute("transform",c);this.svgBubbleCanvas_.setAttribute("transform",c)};Blockly.WorkspaceSvg.prototype.addTopBlock=function(a){Blockly.WorkspaceSvg.superClass_.addTopBlock.call(this,a);Blockly.Realtime.isEnabled()&&!this.options.parentWorkspace&&Blockly.Realtime.addTopBlock(a)};
@@ -1320,8 +1320,8 @@ Blockly.WidgetDiv={};Blockly.WidgetDiv.DIV=null;Blockly.WidgetDiv.owner_=null;Bl
 Blockly.WidgetDiv.hide=function(){Blockly.WidgetDiv.owner_&&(Blockly.WidgetDiv.DIV.style.display="none",Blockly.WidgetDiv.dispose_&&Blockly.WidgetDiv.dispose_(),Blockly.WidgetDiv.owner_=null,Blockly.WidgetDiv.dispose_=null,goog.dom.removeChildren(Blockly.WidgetDiv.DIV))};Blockly.WidgetDiv.isVisible=function(){return!!Blockly.WidgetDiv.owner_};Blockly.WidgetDiv.hideIfOwner=function(a){Blockly.WidgetDiv.owner_==a&&Blockly.WidgetDiv.hide()};
 Blockly.WidgetDiv.position=function(a,b,c,d,e){b<d.y&&(b=d.y);e?a>c.width+d.x&&(a=c.width+d.x):a<d.x&&(a=d.x);Blockly.WidgetDiv.DIV.style.left=a+"px";Blockly.WidgetDiv.DIV.style.top=b+"px"};
 // Copyright 2011 Google Inc.  Apache License 2.0
-Blockly.inject=function(a,b){goog.isString(a)&&(a=document.getElementById(a));if(!goog.dom.contains(document,a))throw"Error: container is not in current document.";var c=Blockly.parseOptions_(b||{}),d,e=function(){goog.dom.removeChildren(a);var b=Blockly.createDom_(a,c);d=Blockly.createMainWorkspace_(b,c);Blockly.init_(d);d.markFocused();Blockly.bindEvent_(b,"focus",d,d.markFocused)};if(c.enableRealtime){var f=document.getElementById("realtime");f&&(f.style.display="block");Blockly.Realtime.startRealtime(e,
-a,c.realtimeOptions)}else e();return d};Blockly.parseToolboxTree_=function(a){a?("string"!=typeof a&&"undefined"==typeof XSLTProcessor&&(a=a.outerHTML),"string"==typeof a&&(a=Blockly.Xml.textToDom(a))):a=null;return a};
+Blockly.inject=function(a,b){goog.isString(a)&&(a=document.getElementById(a));if(!goog.dom.contains(document,a))throw"Error: container is not in current document.";var c=Blockly.parseOptions_(b||{}),d,e=function(){var b=Blockly.createDom_(a,c);d=Blockly.createMainWorkspace_(b,c);Blockly.init_(d);d.markFocused();Blockly.bindEvent_(b,"focus",d,d.markFocused)};if(c.enableRealtime){var f=document.getElementById("realtime");f&&(f.style.display="block");Blockly.Realtime.startRealtime(e,a,c.realtimeOptions)}else e();
+return d};Blockly.parseToolboxTree_=function(a){a?("string"!=typeof a&&"undefined"==typeof XSLTProcessor&&(a=a.outerHTML),"string"==typeof a&&(a=Blockly.Xml.textToDom(a))):a=null;return a};
 Blockly.parseOptions_=function(a){var b=!!a.readOnly;if(b)var c=null,d=!1,e=!1,f=!1,g=!1,h=!1,k=!1;else c=Blockly.parseToolboxTree_(a.toolbox),d=Boolean(c&&c.getElementsByTagName("category").length),e=a.trashcan,void 0===e&&(e=d),f=a.collapse,void 0===f&&(f=d),g=a.comments,void 0===g&&(g=d),h=a.disable,void 0===h&&(h=d),k=a.sounds,void 0===k&&(k=!0);var l=a.scrollbars;void 0===l&&(l=d);var p=a.css;void 0===p&&(p=!0);var m=a.grid||{};m.spacing=m.spacing?parseFloat(m.spacing):0;m.colour||(m.colour=
 "#888");m.length=m.length?parseFloat(m.length):1;m.snap=0<m.spacing&&!!m.snap;var q="https://blockly-demo.appspot.com/static/media/";a.media?q=a.media:a.path&&(q=a.path+"media/");var n=!!a.realtime;return{RTL:!!a.rtl,collapse:f,comments:g,disable:h,readOnly:b,maxBlocks:a.maxBlocks||Infinity,pathToMedia:q,hasCategories:d,hasScrollbars:l,hasTrashcan:e,hasSounds:k,hasCss:p,languageTree:c,gridOptions:m,enableRealtime:n,realtimeOptions:n?a.realtimeOptions:void 0}};
 Blockly.createDom_=function(a,b){a.setAttribute("dir","LTR");goog.ui.Component.setDefaultRightToLeft(b.RTL);Blockly.Css.inject(b.hasCss,b.pathToMedia);var c=Blockly.createSvgElement("svg",{xmlns:"http://www.w3.org/2000/svg","xmlns:html":"http://www.w3.org/1999/xhtml","xmlns:xlink":"http://www.w3.org/1999/xlink",version:"1.1","class":"blocklySvg"},a),d=Blockly.createSvgElement("defs",{},c),e,f;e=Blockly.createSvgElement("filter",{id:"blocklyEmboss"},d);Blockly.createSvgElement("feGaussianBlur",{"in":"SourceAlpha",
diff --git a/core/inject.js b/core/inject.js
index 93599c72e..c3f97054e 100644
--- a/core/inject.js
+++ b/core/inject.js
@@ -50,7 +50,6 @@ Blockly.inject = function(container, opt_options) {
   var options = Blockly.parseOptions_(opt_options || {});
   var workspace;
   var startUi = function() {
-    goog.dom.removeChildren(container);
     var svg = Blockly.createDom_(container, options);
     workspace = Blockly.createMainWorkspace_(svg, options);
     Blockly.init_(workspace);
diff --git a/core/workspace_svg.js b/core/workspace_svg.js
index 44171937c..3c4a31550 100644
--- a/core/workspace_svg.js
+++ b/core/workspace_svg.js
@@ -170,6 +170,10 @@ Blockly.WorkspaceSvg.prototype.dispose = function() {
     this.trashcan.dispose();
     this.trashcan = null;
   }
+  if (!this.options.parentWorkspace) {
+    // Top-most workspace.  Dispose of the SVG too.
+    goog.dom.removeNode(this.options.svg);
+  }
 };
 
 /**
diff --git a/demos/blockfactory/factory.js b/demos/blockfactory/factory.js
index ecae1e816..335e8d7e7 100644
--- a/demos/blockfactory/factory.js
+++ b/demos/blockfactory/factory.js
@@ -396,6 +396,9 @@ var oldDir = null;
 function updatePreview() {
   var newDir = document.getElementById('direction').value;
   if (oldDir != newDir) {
+    if (previewWorkspace) {
+      previewWorkspace.dispose();
+    }
     var rtl = newDir == 'rtl';
     previewWorkspace = Blockly.inject('preview', {rtl: rtl});
     oldDir = newDir;