git-svn-id: svn://192.168.3.15/activex/AVS/Sources/TeamlabOffice/trunk/OfficeWeb@58692 954022d7-b5bf-4e40-9824-e11837661b57

PowerPoint/Drawing/DrawingDocument.js

@@ -3483,7 +3483,7 @@ function CThumbnailsManager()
 
             this.m_bIsUpdate = bIsUpdate;
 
-            if (bIsUpdate)
+            if (bIsUpdate && this.m_oWordControl.m_oScrollThumbApi != null)
             {
                 var y1 = this.m_arrPages[pageNum].top - this.const_border_w;
                 var y2 = this.m_arrPages[pageNum].bottom + this.const_border_w;