diff --git a/chrome/content/zotero/advancedSearch.js b/chrome/content/zotero/advancedSearch.js
index 1d2c3d2f1..fc9c971d6 100644
--- a/chrome/content/zotero/advancedSearch.js
+++ b/chrome/content/zotero/advancedSearch.js
@@ -6,8 +6,9 @@ var ZoteroAdvancedSearch = new function() {
 	this.onDblClick = onDblClick;
 	this.onUnload = onUnload;
 	
+	this.itemsView = false;
+	
 	var _searchBox;
-	var _itemsView;
 	
 	function onLoad() {
 		_searchBox = document.getElementById('zotero-search-box');
@@ -31,18 +32,18 @@ var ZoteroAdvancedSearch = new function() {
 			isSearch: function () { return true; }
 		}
 		
-		if (_itemsView) {
-			_itemsView.unregister();
+		if (this.itemsView) {
+			this.itemsView.unregister();
 		}
 		
-		_itemsView = new Zotero.ItemTreeView(itemGroup, false);
-		document.getElementById('zotero-items-tree').view = _itemsView;
+		this.itemsView = new Zotero.ItemTreeView(itemGroup, false);
+		document.getElementById('zotero-items-tree').view = this.itemsView;
 	}
 	
 	
 	function clear() {
-		if (_itemsView) {
-			_itemsView.unregister();
+		if (this.itemsView) {
+			this.itemsView.unregister();
 		}
 		document.getElementById('zotero-items-tree').view = null;
 		
@@ -90,9 +91,9 @@ var ZoteroAdvancedSearch = new function() {
 			tree.treeBoxObject.getCellAt(event.clientX, event.clientY, row, col, obj);
 			// obj.value == cell/text/image
 			// TODO: handle collection double-click
-			if (obj.value && _itemsView && _itemsView.selection.currentIndex > -1)
+			if (obj.value && this.itemsView && this.itemsView.selection.currentIndex > -1)
 			{
-				var item = _itemsView.getSelectedItems()[0];
+				var item = this.itemsView.getSelectedItems()[0];
 				
 				var wm = Components.classes["@mozilla.org/appshell/window-mediator;1"]
 							   .getService(Components.interfaces.nsIWindowMediator);
@@ -118,8 +119,8 @@ var ZoteroAdvancedSearch = new function() {
 	
 	function onUnload() {
 		// Unregister search from Notifier
-		if (_itemsView) {
-			_itemsView.unregister();
+		if (this.itemsView) {
+			this.itemsView.unregister();
 		}
 	}
 }
diff --git a/chrome/content/zotero/advancedSearch.xul b/chrome/content/zotero/advancedSearch.xul
index 405e6bc63..8ac3fb3af 100644
--- a/chrome/content/zotero/advancedSearch.xul
+++ b/chrome/content/zotero/advancedSearch.xul
@@ -21,6 +21,8 @@
 	
 	<script src="include.js"/>
 	<script src="advancedSearch.js"/>
+	<script src="chrome://global/content/nsDragAndDrop.js"/>
+	<script src="chrome://global/content/nsTransferable.js"/>
 	
 	<hbox>
 		<zoterosearch id="zotero-search-box" oncommand="ZoteroAdvancedSearch.search()" flex="1"/>
@@ -33,7 +35,8 @@
 	</hbox>
 	
 	<tree id="zotero-items-tree" flex="1" hidecolumnpicker="true" seltype="multiple"
-			ondblclick="ZoteroAdvancedSearch.onDblClick(event, this)">
+			ondblclick="ZoteroAdvancedSearch.onDblClick(event, this)"
+			ondraggesture="if (event.target.localName == 'treechildren') { nsDragAndDrop.startDrag(event, ZoteroAdvancedSearch.itemsView); }">
 		<treecols>
 			<treecol
 				id="zotero-items-column-title" primary="true"
diff --git a/chrome/content/zotero/xpcom/itemTreeView.js b/chrome/content/zotero/xpcom/itemTreeView.js
index 50a9fbaea..24f37d0f5 100644
--- a/chrome/content/zotero/xpcom/itemTreeView.js
+++ b/chrome/content/zotero/xpcom/itemTreeView.js
@@ -1046,7 +1046,7 @@ Zotero.ItemTreeView.prototype.canDrop = function(row, orient)
 				// DISABLED: move parent on child drag
 				//var source = item.isRegularItem() ? false : item.getSource();
 				//if (!this._itemGroup.ref.hasItem(source ? source : id))
-				if (!this._itemGroup.ref.hasItem(id))
+				if (this._itemGroup.ref && !this._itemGroup.ref.hasItem(id))
 				{
 					return true;
 				}