--- a/AbstractFileApplicationNoteBookComponent.st	Fri Mar 25 17:10:41 2016 +0100
+++ b/AbstractFileApplicationNoteBookComponent.st	Fri Mar 25 19:41:28 2016 +0100
@@ -71,6 +71,14 @@
     ^ false
 !
 
+isAbstract
+    "Return if this class is an abstract class.
+     True is returned here for myself only; false for subclasses.
+     Abstract subclasses must redefine this again."
+
+    ^ self == AbstractFileApplicationNoteBookComponent.
+!
+
 wantNewApplicationAnyway
 
     ^ true