diff --git a/packages/react-dnd-html5-backend/src/HTML5Backend.js b/packages/react-dnd-html5-backend/src/HTML5Backend.js
index <HASH>..<HASH> 100644
--- a/packages/react-dnd-html5-backend/src/HTML5Backend.js
+++ b/packages/react-dnd-html5-backend/src/HTML5Backend.js
@@ -19,6 +19,15 @@ export default class HTML5Backend {
     this.sourceNodeOptions = {};
     this.enterLeaveCounter = new EnterLeaveCounter();
 
+    this.dragStartSourceIds = [];
+    this.dropTargetIds = [];
+    this.dragEnterTargetIds = [];
+    this.currentNativeSource = null;
+    this.currentNativeHandle = null;
+    this.currentDragSourceNode = null;
+    this.currentDragSourceNodeOffset = null;
+    this.currentDragSourceNodeOffsetChanged = false;
+
     this.getSourceClientOffset = this.getSourceClientOffset.bind(this);
     this.handleTopDragStart = this.handleTopDragStart.bind(this);
     this.handleTopDragStartCapture = this.handleTopDragStartCapture.bind(this);
Initializing class state in the Backend Constructor (#<I>)