diff -r 16457b922100 web.core/src/org/netbeans/modules/web/core/jsploader/BaseJspEditorSupport.java
--- a/web.core/src/org/netbeans/modules/web/core/jsploader/BaseJspEditorSupport.java	Mon Jul 11 18:04:10 2016 +0000
+++ b/web.core/src/org/netbeans/modules/web/core/jsploader/BaseJspEditorSupport.java	Wed Jul 13 17:42:27 2016 +1000
@@ -176,34 +176,26 @@
         //EditorCookie.Observable listener
         addPropertyChangeListener(new PropertyChangeListener() {
 
+            @Override
             public void propertyChange(PropertyChangeEvent evt) {
                 if (evt.getPropertyName().equals(EditorCookie.Observable.PROP_DOCUMENT)) {
                     if (evt.getNewValue() != null) {
                         //document loaded
                         restartParserTask();
                         ((Document)evt.getNewValue()).addDocumentListener(DOCUMENT_LISTENER);
-                    } else {
+                    } else if (evt.getOldValue() != null) {
                         //document closed
-                        //Issue #172631>>>
-                        Object oldDoc = evt.getOldValue();
-                        if(oldDoc == null) {
-                            Logger.getLogger(getClass().getName()).log(Level.INFO, 
-                                    "property change fired with both new and old value null!",
-                                    new IllegalStateException());
-                            return ;
-                        }
-                        //<<<
-                        ((Document)oldDoc).removeDocumentListener(DOCUMENT_LISTENER);
+                        ((Document)evt.getOldValue()).removeDocumentListener(DOCUMENT_LISTENER);
                         //cancel waiting parsing task if there is any
                         //this is largely a workaround for issue #50926
-                        TagLibParseSupport sup = (TagLibParseSupport) getDataObject().getCookie(TagLibParseSupport.class);
+                        TagLibParseSupport sup = getDataObject().getLookup().lookup(TagLibParseSupport.class);
                         if (sup != null) {
                             sup.cancelParsingTask();
                         }
                     }
-
                 }
             }
+
         });
     }