diff --git a/lib/yui/dragdrop/dragdrop.js b/lib/yui/dragdrop/dragdrop.js
index 27d0f1db421..6669f37126a 100644
--- a/lib/yui/dragdrop/dragdrop.js
+++ b/lib/yui/dragdrop/dragdrop.js
@@ -135,7 +135,7 @@ YUI.add('moodle-core-dragdrop', function(Y) {
 
         global_drop_over : function(e) {
             // Check that drop object belong to correct group
-            if (!e.drop.inGroup(this.groups)) {
+            if (!e.drop || !e.drop.inGroup(this.groups)) {
                 return;
             }
             //Get a reference to our drag and drop nodes
@@ -168,7 +168,7 @@ YUI.add('moodle-core-dragdrop', function(Y) {
             // this.lastdroptarget (ghost node we use for indicating where to drop)
             e.drag = e.target;
             // Check that drop object belong to correct group
-            if (!e.drag.target.inGroup(this.groups)) {
+            if (!e.drop || !e.drop.inGroup(this.groups)) {
                 return;
             }
             e.drop = this.lastdroptarget;
@@ -177,7 +177,7 @@ YUI.add('moodle-core-dragdrop', function(Y) {
 
         global_drop_hit : function(e) {
             // Check that drop object belong to correct group
-            if (!e.drop.inGroup(this.groups)) {
+            if (!e.drop || !e.drop.inGroup(this.groups)) {
                 return;
             }
             this.drop_hit(e);