diff --git a/core/delete_area.js b/core/delete_area.js
index 3985fca90ac..ba2b535d0db 100644
--- a/core/delete_area.js
+++ b/core/delete_area.js
@@ -49,6 +49,13 @@ class DeleteArea extends DragTarget {
      * @protected
      */
     this.wouldDelete_ = false;
+
+    /**
+     * The unique id for this component that is used to register with the
+     * ComponentManager.
+     * @type {string}
+     */
+    this.id;
   }
 
   /**
diff --git a/core/drag_target.js b/core/drag_target.js
index 64a3e3ce3f0..71db7477f66 100644
--- a/core/drag_target.js
+++ b/core/drag_target.js
@@ -33,6 +33,19 @@ const {Rect} = goog.requireType('Blockly.utils.Rect');
  * @alias Blockly.DragTarget
  */
 class DragTarget {
+  /**
+   * Constructor for DragTarget. It exists to add the id property and should not
+   * be called directly, only by a subclass.
+   */
+  constructor() {
+    /**
+     * The unique id for this component that is used to register with the
+     * ComponentManager.
+     * @type {string}
+     */
+    this.id;
+  }
+
   /**
    * Handles when a cursor with a block or bubble enters this drag target.
    * @param {!IDraggable} _dragElement The block or bubble currently being
diff --git a/core/interfaces/i_block_dragger.js b/core/interfaces/i_block_dragger.js
index e2108712e33..587da618f0a 100644
--- a/core/interfaces/i_block_dragger.js
+++ b/core/interfaces/i_block_dragger.js
@@ -63,4 +63,9 @@ IBlockDragger.prototype.endDrag;
  */
 IBlockDragger.prototype.getInsertionMarkers;
 
+/**
+ * Sever all links from this object and do any necessary cleanup.
+ */
+IBlockDragger.prototype.dispose;
+
 exports.IBlockDragger = IBlockDragger;
diff --git a/core/interfaces/i_component.js b/core/interfaces/i_component.js
index 3b191ad6f2a..56e25131a4f 100644
--- a/core/interfaces/i_component.js
+++ b/core/interfaces/i_component.js
@@ -32,6 +32,6 @@ const IComponent = function() {};
  * ComponentManager.
  * @type {string}
  */
-IComponent.id;
+IComponent.prototype.id;
 
 exports.IComponent = IComponent;