diff --git a/blockly_compressed.js b/blockly_compressed.js
index 889051b3d..50d3a3ec8 100644
--- a/blockly_compressed.js
+++ b/blockly_compressed.js
@@ -879,8 +879,9 @@ this.foreignObject_.appendChild(a);Blockly.bindEvent_(this.textarea_,"mouseup",t
 Blockly.Comment.prototype.resizeBubble_=function(){var a=this.bubble_.getBubbleSize(),b=2*Blockly.Bubble.BORDER_WIDTH;this.foreignObject_.setAttribute("width",a.width-b);this.foreignObject_.setAttribute("height",a.height-b);this.textarea_.style.width=a.width-b-4+"px";this.textarea_.style.height=a.height-b-4+"px"};
 Blockly.Comment.prototype.setVisible=function(a){if(a!=this.isVisible())if(!this.block_.isEditable()&&!this.textarea_||goog.userAgent.IE)Blockly.Warning.prototype.setVisible.call(this,a);else{var b=this.getText(),c=this.getBubbleSize();a?(this.bubble_=new Blockly.Bubble(this.block_.workspace,this.createEditor_(),this.block_.svgPath_,this.iconX_,this.iconY_,this.width_,this.height_),this.bubble_.registerResizeEvent(this,this.resizeBubble_),this.updateColour(),this.text_=null):(this.bubble_.dispose(),
 this.foreignObject_=this.textarea_=this.bubble_=null);this.setText(b);this.setBubbleSize(c.width,c.height)}};Blockly.Comment.prototype.textareaFocus_=function(a){this.bubble_.promote_();this.textarea_.focus()};Blockly.Comment.prototype.getBubbleSize=function(){return this.isVisible()?this.bubble_.getBubbleSize():{width:this.width_,height:this.height_}};Blockly.Comment.prototype.setBubbleSize=function(a,b){this.textarea_?this.bubble_.setBubbleSize(a,b):(this.width_=a,this.height_=b)};
-Blockly.Comment.prototype.getText=function(){return this.textarea_?this.textarea_.value:this.text_};Blockly.Comment.prototype.setText=function(a){this.textarea_?this.textarea_.value=a:this.text_=a};Blockly.Comment.prototype.dispose=function(){this.block_.comment=null;Blockly.Icon.prototype.dispose.call(this)};Blockly.Connection=function(a,b){this.sourceBlock_=a;this.type=b;this.db_=a.workspace.connectionDBList[b];this.dbOpposite_=a.workspace.connectionDBList[Blockly.OPPOSITE_TYPE[b]];this.hidden_=!this.db_};Blockly.Connection.prototype.targetConnection=null;Blockly.Connection.prototype.check_=null;Blockly.Connection.prototype.shadowDom_=null;Blockly.Connection.prototype.x_=0;Blockly.Connection.prototype.y_=0;Blockly.Connection.prototype.inDB_=!1;
-Blockly.Connection.prototype.dispose=function(){if(this.targetConnection)throw"Disconnect connection before disposing of it.";this.inDB_&&this.db_.removeConnection_(this);Blockly.highlightedConnection_==this&&(Blockly.highlightedConnection_=null);Blockly.localConnection_==this&&(Blockly.localConnection_=null);this.dbOpposite_=this.db_=null};Blockly.Connection.prototype.isSuperior=function(){return this.type==Blockly.INPUT_VALUE||this.type==Blockly.NEXT_STATEMENT};
+Blockly.Comment.prototype.getText=function(){return this.textarea_?this.textarea_.value:this.text_};Blockly.Comment.prototype.setText=function(a){this.textarea_?this.textarea_.value=a:this.text_=a};Blockly.Comment.prototype.dispose=function(){this.block_.comment=null;Blockly.Icon.prototype.dispose.call(this)};Blockly.Connection=function(a,b){this.sourceBlock_=a;this.type=b;a.workspace.connectionDBList&&(this.db_=a.workspace.connectionDBList[b],this.dbOpposite_=a.workspace.connectionDBList[Blockly.OPPOSITE_TYPE[b]],this.hidden_=!this.db_)};Blockly.Connection.prototype.targetConnection=null;Blockly.Connection.prototype.check_=null;Blockly.Connection.prototype.shadowDom_=null;Blockly.Connection.prototype.x_=0;Blockly.Connection.prototype.y_=0;Blockly.Connection.prototype.inDB_=!1;
+Blockly.Connection.prototype.db_=null;Blockly.Connection.prototype.dbOpposite_=null;Blockly.Connection.prototype.hidden_=null;Blockly.Connection.prototype.dispose=function(){if(this.targetConnection)throw"Disconnect connection before disposing of it.";this.inDB_&&this.db_.removeConnection_(this);Blockly.highlightedConnection_==this&&(Blockly.highlightedConnection_=null);Blockly.localConnection_==this&&(Blockly.localConnection_=null);this.dbOpposite_=this.db_=null};
+Blockly.Connection.prototype.isSuperior=function(){return this.type==Blockly.INPUT_VALUE||this.type==Blockly.NEXT_STATEMENT};
 Blockly.Connection.prototype.connect=function(a){if(this.sourceBlock_==a.sourceBlock_)throw"Attempted to connect a block to itself.";if(this.sourceBlock_.workspace!==a.sourceBlock_.workspace)throw"Blocks are on different workspaces.";if(Blockly.OPPOSITE_TYPE[this.type]!=a.type)throw"Attempt to connect incompatible types.";if(this.type==Blockly.INPUT_VALUE||this.type==Blockly.OUTPUT_VALUE){if(this.targetConnection)throw"Source connection already connected (value).";if(a.targetConnection){var b=a.targetBlock();
 b.setParent(null);if(b.isShadow())a.setShadowDom(Blockly.Xml.blockToDom_(b)),b.dispose();else{if(!b.outputConnection)throw"Orphan block does not have an output connection.";for(var c=this.sourceBlock_,d;d=Blockly.Connection.singleConnection_(c,b);)if(c=d.targetBlock(),!c||c.isShadow()){b.outputConnection.connect(d);b=null;break}b&&setTimeout(function(){b.outputConnection.bumpAwayFrom_(a)},Blockly.BUMP_DELAY)}}}else{if(this.targetConnection)throw"Source connection already connected (block).";if(a.targetConnection){if(this.type!=
 Blockly.PREVIOUS_STATEMENT)throw"Can only do a mid-stack connection with the top of a block.";b=a.targetBlock();b.setParent(null);if(!b.previousConnection)throw"Orphan block does not have a previous connection.";for(c=this.sourceBlock_;c.nextConnection;)if(c.nextConnection.targetConnection)c=c.getNextBlock();else{b.previousConnection.checkType_(c.nextConnection)&&(c.nextConnection.connect(b.previousConnection),b=null);break}b&&setTimeout(function(){b.previousConnection.bumpAwayFrom_(a)},Blockly.BUMP_DELAY)}}this.isSuperior()?
@@ -999,8 +1000,8 @@ Blockly.WorkspaceSvg.prototype.onMouseDown_=function(a){this.markFocused();Block
 a.clientY,this.startDragMetrics=this.getMetrics(),this.startScrollX=this.scrollX,this.startScrollY=this.scrollY,"mouseup"in Blockly.bindEvent_.TOUCH_MAP&&(Blockly.onTouchUpWrapper_=Blockly.bindEvent_(document,"mouseup",null,Blockly.onMouseUp_)),Blockly.onMouseMoveWrapper_=Blockly.bindEvent_(document,"mousemove",null,Blockly.onMouseMove_)),a.stopPropagation())};
 Blockly.WorkspaceSvg.prototype.startDrag=function(a,b,c){a=Blockly.mouseToSvg(a,this.options.svg);a.x/=this.scale;a.y/=this.scale;this.dragDeltaX_=b-a.x;this.dragDeltaY_=c-a.y};Blockly.WorkspaceSvg.prototype.moveDrag=function(a){a=Blockly.mouseToSvg(a,this.options.svg);a.x/=this.scale;a.y/=this.scale;return new goog.math.Coordinate(this.dragDeltaX_+a.x,this.dragDeltaY_+a.y)};
 Blockly.WorkspaceSvg.prototype.onMouseWheel_=function(a){Blockly.terminateDrag_();var b=0<a.deltaY?-1:1,c=Blockly.mouseToSvg(a,this.options.svg);this.zoom(c.x,c.y,b);a.preventDefault()};
-Blockly.WorkspaceSvg.prototype.showContextMenu_=function(a){if(!this.options.readOnly){var b=[];if(this.options.collapse){for(var c=!1,d=!1,e=this.getTopBlocks(!0),f=0;f<e.length;f++)for(var g=e[f];g;)g.isCollapsed()?c=!0:d=!0,g=g.getNextBlock();d={enabled:d};d.text=Blockly.Msg.COLLAPSE_ALL;d.callback=function(){for(var a=0,b=0;b<e.length;b++)for(var c=e[b];c;)setTimeout(c.setCollapsed.bind(c,!0),a),c=c.getNextBlock(),a+=10};b.push(d);c={enabled:c};c.text=Blockly.Msg.EXPAND_ALL;c.callback=function(){for(var a=
-0,b=0;b<e.length;b++)for(var c=e[b];c;)setTimeout(c.setCollapsed.bind(c,!1),a),c=c.getNextBlock(),a+=10};b.push(c)}Blockly.ContextMenu.show(a,b,this.RTL)}};Blockly.WorkspaceSvg.prototype.loadAudio_=function(a,b){if(a.length){try{var c=new window.Audio}catch(h){return}for(var d,e=0;e<a.length;e++){var f=a[e],g=f.match(/\.(\w+)$/);if(g&&c.canPlayType("audio/"+g[1])){d=new window.Audio(f);break}}d&&d.play&&(this.SOUNDS_[b]=d)}};
+Blockly.WorkspaceSvg.prototype.showContextMenu_=function(a){if(!this.options.readOnly){var b=[];if(this.options.collapse){for(var c=!1,d=!1,e=this.getTopBlocks(!0),f=0;f<e.length;f++)for(var g=e[f];g;)g.isCollapsed()?c=!0:d=!0,g=g.getNextBlock();var h=function(a){for(var b=0,c=0;c<e.length;c++)for(var d=e[c];d;)setTimeout(d.setCollapsed.bind(d,a),b),d=d.getNextBlock(),b+=10},d={enabled:d};d.text=Blockly.Msg.COLLAPSE_ALL;d.callback=function(){h(!0)};b.push(d);c={enabled:c};c.text=Blockly.Msg.EXPAND_ALL;
+c.callback=function(){h(!1)};b.push(c)}Blockly.ContextMenu.show(a,b,this.RTL)}};Blockly.WorkspaceSvg.prototype.loadAudio_=function(a,b){if(a.length){try{var c=new window.Audio}catch(h){return}for(var d,e=0;e<a.length;e++){var f=a[e],g=f.match(/\.(\w+)$/);if(g&&c.canPlayType("audio/"+g[1])){d=new window.Audio(f);break}}d&&d.play&&(this.SOUNDS_[b]=d)}};
 Blockly.WorkspaceSvg.prototype.preloadAudio_=function(){for(var a in this.SOUNDS_){var b=this.SOUNDS_[a];b.volume=.01;b.play();b.pause();if(goog.userAgent.IPAD||goog.userAgent.IPHONE)break}};
 Blockly.WorkspaceSvg.prototype.playAudio=function(a,b){var c=this.SOUNDS_[a];c?(c=goog.userAgent.DOCUMENT_MODE&&9===goog.userAgent.DOCUMENT_MODE||goog.userAgent.IPAD||goog.userAgent.ANDROID?c:c.cloneNode(),c.volume=void 0===b?1:b,c.play()):this.options.parentWorkspace&&this.options.parentWorkspace.playAudio(a,b)};
 Blockly.WorkspaceSvg.prototype.updateToolbox=function(a){if(a=Blockly.parseToolboxTree_(a)){if(!this.options.languageTree)throw"Existing toolbox is null.  Can't create new toolbox.";if(this.options.hasCategories){if(!this.toolbox_)throw"Existing toolbox has no categories.  Can't change mode.";this.options.languageTree=a;this.toolbox_.populate_(a)}else{if(!this.flyout_)throw"Existing toolbox has categories.  Can't change mode.";this.options.languageTree=a;this.flyout_.show(a.childNodes)}}else if(this.options.languageTree)throw"Can't nullify an existing toolbox.";
diff --git a/core/connection.js b/core/connection.js
index 04efc3e29..f7dc3b2af 100644
--- a/core/connection.js
+++ b/core/connection.js
@@ -42,10 +42,12 @@ Blockly.Connection = function(source, type) {
   /** @type {number} */
   this.type = type;
   // Shortcut for the databases for this connection's workspace.
-  this.db_ = source.workspace.connectionDBList[type];
-  this.dbOpposite_ =
-      source.workspace.connectionDBList[Blockly.OPPOSITE_TYPE[type]];
-  this.hidden_ = !this.db_;
+  if (source.workspace.connectionDBList) {
+    this.db_ = source.workspace.connectionDBList[type];
+    this.dbOpposite_ =
+        source.workspace.connectionDBList[Blockly.OPPOSITE_TYPE[type]];
+    this.hidden_ = !this.db_;
+  }
 };
 
 /**
@@ -89,6 +91,28 @@ Blockly.Connection.prototype.y_ = 0;
  */
 Blockly.Connection.prototype.inDB_ = false;
 
+/**
+ * Connection database for connections of this type on the current workspace.
+ * @type {Blockly.ConnectionDB}
+ * @private
+ */
+Blockly.Connection.prototype.db_ = null;
+
+/**
+ * Connection database for connections compatible with this type on the
+ * current workspace.
+ * @type {Blockly.ConnectionDB}
+ * @private
+ */
+Blockly.Connection.prototype.dbOpposite_ = null;
+
+/**
+ * Whether this connections is hidden (not tracked in a database) or not.
+ * @type {boolean}
+ * @private
+ */
+Blockly.Connection.prototype.hidden_ = null;
+
 /**
  * Sever all links to this connection (not including from the source object).
  */
diff --git a/core/workspace_svg.js b/core/workspace_svg.js
index e4f640948..9e5d1e2ba 100644
--- a/core/workspace_svg.js
+++ b/core/workspace_svg.js
@@ -679,10 +679,10 @@ Blockly.WorkspaceSvg.prototype.showContextMenu_ = function(e) {
 
     /*
      * Option to collapse or expand top blocks
-     * @param {bool} shouldCollapse whether a block should collapse
+     * @param {boolean} shouldCollapse Whether a block should collapse.
      * @private
      */
-    function toggleOption(shouldCollapse) {
+    var toggleOption = function(shouldCollapse) {
       var ms = 0;
       for (var i = 0; i < topBlocks.length; i++) {
         var block = topBlocks[i];
@@ -692,7 +692,7 @@ Blockly.WorkspaceSvg.prototype.showContextMenu_ = function(e) {
           ms += COLLAPSE_DELAY;
         }
       }
-    }
+    };
 
     // Option to collapse top blocks.
     var collapseOption = {enabled: hasExpandedBlocks};