Fix rare race condition bug

Author: OpenHypervideo

src/player/modules/AnnotationsController/module.js

@@ -722,7 +722,9 @@
 
         } else {
 
-            ViewVideo.AnnotationTimeline.droppable('destroy');
+            if (ViewVideo.AnnotationTimeline.hasClass('ui-droppable')) {
+                ViewVideo.AnnotationTimeline.droppable('destroy');
+            }
 
         }
 

src/player/modules/CodeSnippetsController/module.js

@@ -434,8 +434,9 @@ FrameTrail.defineModule('CodeSnippetsController', function(FrameTrail){
 
         } else {
 
-
-            ViewVideo.CodeSnippetTimeline.droppable('destroy');
+            if (ViewVideo.CodeSnippetTimeline.hasClass('ui-droppable')) {
+                ViewVideo.CodeSnippetTimeline.droppable('destroy');
+            }
 
         }
 

src/player/modules/OverlaysController/module.js

@@ -576,7 +576,9 @@ FrameTrail.defineModule('OverlaysController', function(FrameTrail){
 
         } else {
 
-            ViewVideo.OverlayContainer.droppable('destroy');
+            if (ViewVideo.OverlayContainer.hasClass('ui-droppable')) {
+                ViewVideo.OverlayContainer.droppable('destroy');
+            }
 
         }